diff --git a/src/init.cpp b/src/init.cpp
index aaa5f06c7..7054264c0 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -234,6 +234,26 @@ bool static Bind(const CService &addr, unsigned int flags) {
     return true;
 }
 
+void OnRPCStopped()
+{
+    cvBlockChange.notify_all();
+    LogPrint("rpc", "RPC stopped.\n");
+}
+
+void OnRPCPreCommand(const CRPCCommand& cmd)
+{
+#ifdef ENABLE_WALLET
+    if (cmd.reqWallet && !pwalletMain)
+        throw JSONRPCError(RPC_METHOD_NOT_FOUND, "Method not found (disabled)");
+#endif
+
+    // Observe safe mode
+    string strWarning = GetWarnings("rpc");
+    if (strWarning != "" && !GetBoolArg("-disablesafemode", false) &&
+        !cmd.okSafeMode)
+        throw JSONRPCError(RPC_FORBIDDEN_BY_SAFE_MODE, string("Safe mode: ") + strWarning);
+}
+
 std::string HelpMessage(HelpMessageMode mode)
 {
     // When adding new options to the categories, please keep and ensure alphabetical ordering.
@@ -802,6 +822,8 @@ bool AppInit2(boost::thread_group& threadGroup)
     if (fServer)
     {
         uiInterface.InitMessage.connect(SetRPCWarmupStatus);
+        RPCServer::OnStopped(&OnRPCStopped);
+        RPCServer::OnPreCommand(&OnRPCPreCommand);
         StartRPCThreads();
     }
 
diff --git a/src/rpcblockchain.cpp b/src/rpcblockchain.cpp
index cfc559d19..293d6d561 100644
--- a/src/rpcblockchain.cpp
+++ b/src/rpcblockchain.cpp
@@ -105,6 +105,7 @@ Value getblockcount(const Array& params, bool fHelp)
             + HelpExampleRpc("getblockcount", "")
         );
 
+    LOCK(cs_main);
     return chainActive.Height();
 }
 
@@ -121,6 +122,7 @@ Value getbestblockhash(const Array& params, bool fHelp)
             + HelpExampleRpc("getbestblockhash", "")
         );
 
+    LOCK(cs_main);
     return chainActive.Tip()->GetBlockHash().GetHex();
 }
 
@@ -137,6 +139,7 @@ Value getdifficulty(const Array& params, bool fHelp)
             + HelpExampleRpc("getdifficulty", "")
         );
 
+    LOCK(cs_main);
     return GetDifficulty();
 }
 
@@ -173,6 +176,8 @@ Value getrawmempool(const Array& params, bool fHelp)
             + HelpExampleRpc("getrawmempool", "true")
         );
 
+    LOCK(cs_main);
+
     bool fVerbose = false;
     if (params.size() > 0)
         fVerbose = params[0].get_bool();
@@ -233,6 +238,8 @@ Value getblockhash(const Array& params, bool fHelp)
             + HelpExampleRpc("getblockhash", "1000")
         );
 
+    LOCK(cs_main);
+
     int nHeight = params[0].get_int();
     if (nHeight < 0 || nHeight > chainActive.Height())
         throw JSONRPCError(RPC_INVALID_PARAMETER, "Block height out of range");
@@ -277,6 +284,8 @@ Value getblock(const Array& params, bool fHelp)
             + HelpExampleRpc("getblock", "\"00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09\"")
         );
 
+    LOCK(cs_main);
+
     std::string strHash = params[0].get_str();
     uint256 hash(uint256S(strHash));
 
@@ -326,6 +335,8 @@ Value gettxoutsetinfo(const Array& params, bool fHelp)
             + HelpExampleRpc("gettxoutsetinfo", "")
         );
 
+    LOCK(cs_main);
+
     Object ret;
 
     CCoinsStats stats;
@@ -380,6 +391,8 @@ Value gettxout(const Array& params, bool fHelp)
             + HelpExampleRpc("gettxout", "\"txid\", 1")
         );
 
+    LOCK(cs_main);
+
     Object ret;
 
     std::string strHash = params[0].get_str();
@@ -436,6 +449,8 @@ Value verifychain(const Array& params, bool fHelp)
             + HelpExampleRpc("verifychain", "")
         );
 
+    LOCK(cs_main);
+
     int nCheckLevel = GetArg("-checklevel", 3);
     int nCheckDepth = GetArg("-checkblocks", 288);
     if (params.size() > 0)
@@ -467,6 +482,8 @@ Value getblockchaininfo(const Array& params, bool fHelp)
             + HelpExampleRpc("getblockchaininfo", "")
         );
 
+    LOCK(cs_main);
+
     Object obj;
     obj.push_back(Pair("chain",                 Params().NetworkIDString()));
     obj.push_back(Pair("blocks",                (int)chainActive.Height()));
@@ -526,6 +543,8 @@ Value getchaintips(const Array& params, bool fHelp)
             + HelpExampleRpc("getchaintips", "")
         );
 
+    LOCK(cs_main);
+
     /* Build up a list of chain tips.  We start with the list of all
        known blocks, and successively remove blocks that appear as pprev
        of another block.  */
diff --git a/src/rpcdump.cpp b/src/rpcdump.cpp
index 8666779cc..b9c92a06c 100644
--- a/src/rpcdump.cpp
+++ b/src/rpcdump.cpp
@@ -91,6 +91,8 @@ Value importprivkey(const Array& params, bool fHelp)
             + HelpExampleRpc("importprivkey", "\"mykey\", \"testing\", false")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     EnsureWalletIsUnlocked();
 
     string strSecret = params[0].get_str();
@@ -158,6 +160,8 @@ Value importaddress(const Array& params, bool fHelp)
             + HelpExampleRpc("importaddress", "\"myaddress\", \"testing\", false")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     CScript script;
 
     CBitcoinAddress address(params[0].get_str());
@@ -223,6 +227,8 @@ Value importwallet(const Array& params, bool fHelp)
             + HelpExampleRpc("importwallet", "\"test\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     EnsureWalletIsUnlocked();
 
     ifstream file;
@@ -322,6 +328,8 @@ Value dumpprivkey(const Array& params, bool fHelp)
             + HelpExampleRpc("dumpprivkey", "\"myaddress\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     EnsureWalletIsUnlocked();
 
     string strAddress = params[0].get_str();
@@ -351,6 +359,8 @@ Value dumpwallet(const Array& params, bool fHelp)
             + HelpExampleRpc("dumpwallet", "\"test\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     EnsureWalletIsUnlocked();
 
     ofstream file;
diff --git a/src/rpcmining.cpp b/src/rpcmining.cpp
index 5df5de66d..369b3fb4d 100644
--- a/src/rpcmining.cpp
+++ b/src/rpcmining.cpp
@@ -88,6 +88,7 @@ Value getnetworkhashps(const Array& params, bool fHelp)
             + HelpExampleRpc("getnetworkhashps", "")
        );
 
+    LOCK(cs_main);
     return GetNetworkHashPS(params.size() > 0 ? params[0].get_int() : 120, params.size() > 1 ? params[1].get_int() : -1);
 }
 
@@ -107,6 +108,7 @@ Value getgenerate(const Array& params, bool fHelp)
             + HelpExampleRpc("getgenerate", "")
         );
 
+    LOCK(cs_main);
     return GetBoolArg("-gen", false);
 }
 
@@ -200,7 +202,6 @@ Value setgenerate(const Array& params, bool fHelp)
 
     return Value::null;
 }
-
 #endif
 
 
@@ -228,6 +229,9 @@ Value getmininginfo(const Array& params, bool fHelp)
             + HelpExampleRpc("getmininginfo", "")
         );
 
+
+    LOCK(cs_main);
+
     Object obj;
     obj.push_back(Pair("blocks",           (int)chainActive.Height()));
     obj.push_back(Pair("currentblocksize", (uint64_t)nLastBlockSize));
@@ -268,8 +272,9 @@ Value prioritisetransaction(const Array& params, bool fHelp)
             + HelpExampleRpc("prioritisetransaction", "\"txid\", 0.0, 10000")
         );
 
-    uint256 hash = ParseHashStr(params[0].get_str(), "txid");
+    LOCK(cs_main);
 
+    uint256 hash = ParseHashStr(params[0].get_str(), "txid");
     CAmount nAmount = params[2].get_int64();
 
     mempool.PrioritiseTransaction(hash, params[0].get_str(), params[1].get_real(), nAmount);
@@ -358,6 +363,8 @@ Value getblocktemplate(const Array& params, bool fHelp)
             + HelpExampleRpc("getblocktemplate", "")
          );
 
+    LOCK(cs_main);
+
     std::string strMode = "template";
     Value lpval = Value::null;
     if (params.size() > 0)
diff --git a/src/rpcmisc.cpp b/src/rpcmisc.cpp
index 3d647a0d2..8d260b1cc 100644
--- a/src/rpcmisc.cpp
+++ b/src/rpcmisc.cpp
@@ -69,6 +69,12 @@ Value getinfo(const Array& params, bool fHelp)
             + HelpExampleRpc("getinfo", "")
         );
 
+#ifdef ENABLE_WALLET
+    LOCK2(cs_main, pwalletMain ? &pwalletMain->cs_wallet : NULL);
+#else
+    LOCK(cs_main);
+#endif
+
     proxyType proxy;
     GetProxy(NET_IPV4, proxy);
 
@@ -172,6 +178,12 @@ Value validateaddress(const Array& params, bool fHelp)
             + HelpExampleRpc("validateaddress", "\"1PSSGeFHDnKNxiEyFrD1wcEaHr9hrQDDWc\"")
         );
 
+#ifdef ENABLE_WALLET
+    LOCK2(cs_main, pwalletMain ? &pwalletMain->cs_wallet : NULL);
+#else
+    LOCK(cs_main);
+#endif
+
     CBitcoinAddress address(params[0].get_str());
     bool isValid = address.IsValid();
 
@@ -329,6 +341,8 @@ Value verifymessage(const Array& params, bool fHelp)
             + HelpExampleRpc("verifymessage", "\"1D1ZrZNe3JUo7ZycKEYQQiQAWd9y54F4XZ\", \"signature\", \"my message\"")
         );
 
+    LOCK(cs_main);
+
     string strAddress  = params[0].get_str();
     string strSign     = params[1].get_str();
     string strMessage  = params[2].get_str();
@@ -372,6 +386,8 @@ Value setmocktime(const Array& params, bool fHelp)
     if (!Params().MineBlocksOnDemand())
         throw runtime_error("setmocktime for regression testing (-regtest mode) only");
 
+    LOCK(cs_main);
+
     RPCTypeCheck(params, boost::assign::list_of(int_type));
     SetMockTime(params[0].get_int64());
 
diff --git a/src/rpcnet.cpp b/src/rpcnet.cpp
index f0fadb598..6306fd440 100644
--- a/src/rpcnet.cpp
+++ b/src/rpcnet.cpp
@@ -34,7 +34,8 @@ Value getconnectioncount(const Array& params, bool fHelp)
             + HelpExampleRpc("getconnectioncount", "")
         );
 
-    LOCK(cs_vNodes);
+    LOCK2(cs_main, cs_vNodes);
+
     return (int)vNodes.size();
 }
 
@@ -52,7 +53,8 @@ Value ping(const Array& params, bool fHelp)
         );
 
     // Request that each node send a ping during next message processing pass
-    LOCK(cs_vNodes);
+    LOCK2(cs_main, cs_vNodes);
+
     BOOST_FOREACH(CNode* pNode, vNodes) {
         pNode->fPingQueued = true;
     }
@@ -113,6 +115,8 @@ Value getpeerinfo(const Array& params, bool fHelp)
             + HelpExampleRpc("getpeerinfo", "")
         );
 
+    LOCK(cs_main);
+
     vector<CNodeStats> vstats;
     CopyNodeStats(vstats);
 
@@ -411,6 +415,8 @@ Value getnetworkinfo(const Array& params, bool fHelp)
             + HelpExampleRpc("getnetworkinfo", "")
         );
 
+    LOCK(cs_main);
+
     Object obj;
     obj.push_back(Pair("version",       CLIENT_VERSION));
     obj.push_back(Pair("subversion",
diff --git a/src/rpcrawtransaction.cpp b/src/rpcrawtransaction.cpp
index 2b108bf58..0859c0e61 100644
--- a/src/rpcrawtransaction.cpp
+++ b/src/rpcrawtransaction.cpp
@@ -169,6 +169,8 @@ Value getrawtransaction(const Array& params, bool fHelp)
             + HelpExampleRpc("getrawtransaction", "\"mytxid\", 1")
         );
 
+    LOCK(cs_main);
+
     uint256 hash = ParseHashV(params[0], "parameter 1");
 
     bool fVerbose = false;
@@ -256,6 +258,7 @@ Value listunspent(const Array& params, bool fHelp)
     Array results;
     vector<COutput> vecOutputs;
     assert(pwalletMain != NULL);
+    LOCK2(cs_main, pwalletMain->cs_wallet);
     pwalletMain->AvailableCoins(vecOutputs, false);
     BOOST_FOREACH(const COutput& out, vecOutputs) {
         if (out.nDepth < nMinDepth || out.nDepth > nMaxDepth)
@@ -334,6 +337,7 @@ Value createrawtransaction(const Array& params, bool fHelp)
             + HelpExampleRpc("createrawtransaction", "\"[{\\\"txid\\\":\\\"myid\\\",\\\"vout\\\":0}]\", \"{\\\"address\\\":0.01}\"")
         );
 
+    LOCK(cs_main);
     RPCTypeCheck(params, boost::assign::list_of(array_type)(obj_type));
 
     Array inputs = params[0].get_array();
@@ -428,6 +432,7 @@ Value decoderawtransaction(const Array& params, bool fHelp)
             + HelpExampleRpc("decoderawtransaction", "\"hexstring\"")
         );
 
+    LOCK(cs_main);
     RPCTypeCheck(params, boost::assign::list_of(str_type));
 
     CTransaction tx;
@@ -466,6 +471,7 @@ Value decodescript(const Array& params, bool fHelp)
             + HelpExampleRpc("decodescript", "\"hexstring\"")
         );
 
+    LOCK(cs_main);
     RPCTypeCheck(params, boost::assign::list_of(str_type));
 
     Object r;
@@ -532,6 +538,11 @@ Value signrawtransaction(const Array& params, bool fHelp)
             + HelpExampleRpc("signrawtransaction", "\"myhex\"")
         );
 
+#ifdef ENABLE_WALLET
+    LOCK2(cs_main, pwalletMain ? &pwalletMain->cs_wallet : NULL);
+#else
+    LOCK(cs_main);
+#endif
     RPCTypeCheck(params, boost::assign::list_of(str_type)(array_type)(array_type)(str_type), true);
 
     vector<unsigned char> txData(ParseHexV(params[0], "argument 1"));
@@ -591,7 +602,7 @@ Value signrawtransaction(const Array& params, bool fHelp)
         }
     }
 #ifdef ENABLE_WALLET
-    else
+    else if (pwalletMain)
         EnsureWalletIsUnlocked();
 #endif
 
@@ -722,6 +733,7 @@ Value sendrawtransaction(const Array& params, bool fHelp)
             + HelpExampleRpc("sendrawtransaction", "\"signedhex\"")
         );
 
+    LOCK(cs_main);
     RPCTypeCheck(params, boost::assign::list_of(str_type)(bool_type));
 
     // parse hex string from parameter
diff --git a/src/rpcserver.cpp b/src/rpcserver.cpp
index e4f23d56d..f5f8bb22a 100644
--- a/src/rpcserver.cpp
+++ b/src/rpcserver.cpp
@@ -7,9 +7,11 @@
 
 #include "base58.h"
 #include "init.h"
-#include "main.h"
+#include "random.h"
+#include "sync.h"
 #include "ui_interface.h"
 #include "util.h"
+#include "utilstrencodings.h"
 #ifdef ENABLE_WALLET
 #include "wallet.h"
 #endif
@@ -23,11 +25,13 @@
 #include <boost/iostreams/concepts.hpp>
 #include <boost/iostreams/stream.hpp>
 #include <boost/shared_ptr.hpp>
+#include <boost/signals2/signal.hpp>
 #include <boost/thread.hpp>
 #include "json/json_spirit_writer_template.h"
 
 using namespace boost::asio;
 using namespace json_spirit;
+using namespace RPCServer;
 using namespace std;
 
 static std::string strRPCUserColonPass;
@@ -46,6 +50,34 @@ static boost::asio::io_service::work *rpc_dummy_work = NULL;
 static std::vector<CSubNet> rpc_allow_subnets; //!< List of subnets to allow RPC connections from
 static std::vector< boost::shared_ptr<ip::tcp::acceptor> > rpc_acceptors;
 
+static struct CRPCSignals
+{
+    boost::signals2::signal<void ()> Started;
+    boost::signals2::signal<void ()> Stopped;
+    boost::signals2::signal<void (const CRPCCommand&)> PreCommand;
+    boost::signals2::signal<void (const CRPCCommand&)> PostCommand;
+} g_rpcSignals;
+
+void RPCServer::OnStarted(boost::function<void ()> slot)
+{
+    g_rpcSignals.Started.connect(slot);
+}
+
+void RPCServer::OnStopped(boost::function<void ()> slot)
+{
+    g_rpcSignals.Stopped.connect(slot);
+}
+
+void RPCServer::OnPreCommand(boost::function<void (const CRPCCommand&)> slot)
+{
+    g_rpcSignals.PreCommand.connect(boost::bind(slot, _1));
+}
+
+void RPCServer::OnPostCommand(boost::function<void (const CRPCCommand&)> slot)
+{
+    g_rpcSignals.PostCommand.connect(boost::bind(slot, _1));
+}
+
 void RPCTypeCheck(const Array& params,
                   const list<Value_type>& typesExpected,
                   bool fAllowNull)
@@ -693,6 +725,7 @@ void StartRPCThreads()
     for (int i = 0; i < GetArg("-rpcthreads", 4); i++)
         rpc_worker_group->create_thread(boost::bind(&boost::asio::io_service::run, rpc_io_service));
     fRPCRunning = true;
+    g_rpcSignals.Started();
 }
 
 void StartDummyRPCThread()
@@ -735,7 +768,7 @@ void StopRPCThreads()
     deadlineTimers.clear();
 
     rpc_io_service->stop();
-    cvBlockChange.notify_all();
+    g_rpcSignals.Stopped();
     if (rpc_worker_group != NULL)
         rpc_worker_group->join_all();
     delete rpc_dummy_work; rpc_dummy_work = NULL;
@@ -978,45 +1011,20 @@ json_spirit::Value CRPCTable::execute(const std::string &strMethod, const json_s
     const CRPCCommand *pcmd = tableRPC[strMethod];
     if (!pcmd)
         throw JSONRPCError(RPC_METHOD_NOT_FOUND, "Method not found");
-#ifdef ENABLE_WALLET
-    if (pcmd->reqWallet && !pwalletMain)
-        throw JSONRPCError(RPC_METHOD_NOT_FOUND, "Method not found (disabled)");
-#endif
 
-    // Observe safe mode
-    string strWarning = GetWarnings("rpc");
-    if (strWarning != "" && !GetBoolArg("-disablesafemode", false) &&
-        !pcmd->okSafeMode)
-        throw JSONRPCError(RPC_FORBIDDEN_BY_SAFE_MODE, string("Safe mode: ") + strWarning);
+    g_rpcSignals.PreCommand(*pcmd);
 
     try
     {
         // Execute
-        Value result;
-        {
-            if (pcmd->threadSafe)
-                result = pcmd->actor(params, false);
-#ifdef ENABLE_WALLET
-            else if (!pwalletMain) {
-                LOCK(cs_main);
-                result = pcmd->actor(params, false);
-            } else {
-                LOCK2(cs_main, pwalletMain->cs_wallet);
-                result = pcmd->actor(params, false);
-            }
-#else // ENABLE_WALLET
-            else {
-                LOCK(cs_main);
-                result = pcmd->actor(params, false);
-            }
-#endif // !ENABLE_WALLET
-        }
-        return result;
+        return pcmd->actor(params, false);
     }
     catch (const std::exception& e)
     {
         throw JSONRPCError(RPC_MISC_ERROR, e.what());
     }
+
+    g_rpcSignals.PostCommand(*pcmd);
 }
 
 std::string HelpExampleCli(string methodname, string args){
diff --git a/src/rpcserver.h b/src/rpcserver.h
index 1b94b758f..41cd9da16 100644
--- a/src/rpcserver.h
+++ b/src/rpcserver.h
@@ -19,6 +19,16 @@
 #include "json/json_spirit_utils.h"
 #include "json/json_spirit_writer_template.h"
 
+class CRPCCommand;
+
+namespace RPCServer
+{
+    void OnStarted(boost::function<void ()> slot);
+    void OnStopped(boost::function<void ()> slot);
+    void OnPreCommand(boost::function<void (const CRPCCommand&)> slot);
+    void OnPostCommand(boost::function<void (const CRPCCommand&)> slot);
+}
+
 class CBlockIndex;
 class CNetAddr;
 
diff --git a/src/rpcwallet.cpp b/src/rpcwallet.cpp
index 6ad3ee54d..338b64850 100644
--- a/src/rpcwallet.cpp
+++ b/src/rpcwallet.cpp
@@ -90,6 +90,8 @@ Value getnewaddress(const Array& params, bool fHelp)
             + HelpExampleRpc("getnewaddress", "")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     // Parse the account first so we don't generate a key if there's an error
     string strAccount;
     if (params.size() > 0)
@@ -164,13 +166,14 @@ Value getaccountaddress(const Array& params, bool fHelp)
             + HelpExampleRpc("getaccountaddress", "\"myaccount\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     // Parse the account first so we don't generate a key if there's an error
     string strAccount = AccountFromValue(params[0]);
 
     Value ret;
 
     ret = GetAccountAddress(strAccount).ToString();
-
     return ret;
 }
 
@@ -189,6 +192,8 @@ Value getrawchangeaddress(const Array& params, bool fHelp)
             + HelpExampleRpc("getrawchangeaddress", "")
        );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     if (!pwalletMain->IsLocked())
         pwalletMain->TopUpKeyPool();
 
@@ -219,11 +224,12 @@ Value setaccount(const Array& params, bool fHelp)
             + HelpExampleRpc("setaccount", "\"1D1ZrZNe3JUo7ZycKEYQQiQAWd9y54F4XZ\", \"tabby\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     CBitcoinAddress address(params[0].get_str());
     if (!address.IsValid())
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid Bitcoin address");
 
-
     string strAccount;
     if (params.size() > 1)
         strAccount = AccountFromValue(params[1]);
@@ -262,6 +268,8 @@ Value getaccount(const Array& params, bool fHelp)
             + HelpExampleRpc("getaccount", "\"1D1ZrZNe3JUo7ZycKEYQQiQAWd9y54F4XZ\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     CBitcoinAddress address(params[0].get_str());
     if (!address.IsValid())
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid Bitcoin address");
@@ -292,6 +300,8 @@ Value getaddressesbyaccount(const Array& params, bool fHelp)
             + HelpExampleRpc("getaddressesbyaccount", "\"tabby\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     string strAccount = AccountFromValue(params[0]);
 
     // Find all addresses that have the given account
@@ -363,6 +373,8 @@ Value sendtoaddress(const Array& params, bool fHelp)
             + HelpExampleRpc("sendtoaddress", "\"1M72Sfpbz1BPpXFHz9m3CdqATR44Jvaydd\", 0.1, \"donation\", \"seans outpost\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     CBitcoinAddress address(params[0].get_str());
     if (!address.IsValid())
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid Bitcoin address");
@@ -409,6 +421,8 @@ Value listaddressgroupings(const Array& params, bool fHelp)
             + HelpExampleRpc("listaddressgroupings", "")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     Array jsonGroupings;
     map<CTxDestination, CAmount> balances = pwalletMain->GetAddressBalances();
     BOOST_FOREACH(set<CTxDestination> grouping, pwalletMain->GetAddressGroupings())
@@ -454,6 +468,8 @@ Value signmessage(const Array& params, bool fHelp)
             + HelpExampleRpc("signmessage", "\"1D1ZrZNe3JUo7ZycKEYQQiQAWd9y54F4XZ\", \"my message\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     EnsureWalletIsUnlocked();
 
     string strAddress = params[0].get_str();
@@ -504,6 +520,8 @@ Value getreceivedbyaddress(const Array& params, bool fHelp)
             + HelpExampleRpc("getreceivedbyaddress", "\"1D1ZrZNe3JUo7ZycKEYQQiQAWd9y54F4XZ\", 6")
        );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     // Bitcoin address
     CBitcoinAddress address = CBitcoinAddress(params[0].get_str());
     if (!address.IsValid())
@@ -557,6 +575,8 @@ Value getreceivedbyaccount(const Array& params, bool fHelp)
             + HelpExampleRpc("getreceivedbyaccount", "\"tabby\", 6")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     // Minimum confirmations
     int nMinDepth = 1;
     if (params.size() > 1)
@@ -643,6 +663,8 @@ Value getbalance(const Array& params, bool fHelp)
             + HelpExampleRpc("getbalance", "\"*\", 6")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     if (params.size() == 0)
         return  ValueFromAmount(pwalletMain->GetBalance());
 
@@ -695,6 +717,9 @@ Value getunconfirmedbalance(const Array &params, bool fHelp)
         throw runtime_error(
                 "getunconfirmedbalance\n"
                 "Returns the server's total unconfirmed balance\n");
+
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     return ValueFromAmount(pwalletMain->GetUnconfirmedBalance());
 }
 
@@ -721,6 +746,8 @@ Value movecmd(const Array& params, bool fHelp)
             + HelpExampleRpc("move", "\"timotei\", \"akiko\", 0.01, 6, \"happy birthday!\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     string strFrom = AccountFromValue(params[0]);
     string strTo = AccountFromValue(params[1]);
     CAmount nAmount = AmountFromValue(params[2]);
@@ -793,6 +820,8 @@ Value sendfrom(const Array& params, bool fHelp)
             + HelpExampleRpc("sendfrom", "\"tabby\", \"1M72Sfpbz1BPpXFHz9m3CdqATR44Jvaydd\", 0.01, 6, \"donation\", \"seans outpost\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     string strAccount = AccountFromValue(params[0]);
     CBitcoinAddress address(params[1].get_str());
     if (!address.IsValid())
@@ -850,6 +879,8 @@ Value sendmany(const Array& params, bool fHelp)
             + HelpExampleRpc("sendmany", "\"\", \"{\\\"1D1ZrZNe3JUo7ZycKEYQQiQAWd9y54F4XZ\\\":0.01,\\\"1353tsE8YMTA4EuV7dgUXGjNFf9KpVvKHz\\\":0.02}\", 6, \"testing\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     string strAccount = AccountFromValue(params[0]);
     Object sendTo = params[1].get_obj();
     int nMinDepth = 1;
@@ -935,6 +966,8 @@ Value addmultisigaddress(const Array& params, bool fHelp)
         throw runtime_error(msg);
     }
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     string strAccount;
     if (params.size() > 2)
         strAccount = AccountFromValue(params[2]);
@@ -1110,6 +1143,8 @@ Value listreceivedbyaddress(const Array& params, bool fHelp)
             + HelpExampleRpc("listreceivedbyaddress", "6, true, true")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     return ListReceived(params, false);
 }
 
@@ -1141,6 +1176,8 @@ Value listreceivedbyaccount(const Array& params, bool fHelp)
             + HelpExampleRpc("listreceivedbyaccount", "6, true, true")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     return ListReceived(params, true);
 }
 
@@ -1292,6 +1329,8 @@ Value listtransactions(const Array& params, bool fHelp)
             + HelpExampleRpc("listtransactions", "\"*\", 20, 100")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     string strAccount = "*";
     if (params.size() > 0)
         strAccount = params[0].get_str();
@@ -1372,6 +1411,8 @@ Value listaccounts(const Array& params, bool fHelp)
             + HelpExampleRpc("listaccounts", "6")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     int nMinDepth = 1;
     if (params.size() > 0)
         nMinDepth = params[0].get_int();
@@ -1460,6 +1501,8 @@ Value listsinceblock(const Array& params, bool fHelp)
             + HelpExampleRpc("listsinceblock", "\"000000000000000bacf66f7497b7dc45ef753ee9a7d38571037cdb1a57f663ad\", 6")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     CBlockIndex *pindex = NULL;
     int target_confirms = 1;
     isminefilter filter = ISMINE_SPENDABLE;
@@ -1546,6 +1589,8 @@ Value gettransaction(const Array& params, bool fHelp)
             + HelpExampleRpc("gettransaction", "\"1075db55d416d3ca199f55b6084e2115b9345e16c5cf302fc80e9d5fbf5d48d\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     uint256 hash;
     hash.SetHex(params[0].get_str());
 
@@ -1594,6 +1639,8 @@ Value backupwallet(const Array& params, bool fHelp)
             + HelpExampleRpc("backupwallet", "\"backup.dat\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     string strDest = params[0].get_str();
     if (!BackupWallet(*pwalletMain, strDest))
         throw JSONRPCError(RPC_WALLET_ERROR, "Error: Wallet backup failed!");
@@ -1616,6 +1663,8 @@ Value keypoolrefill(const Array& params, bool fHelp)
             + HelpExampleRpc("keypoolrefill", "")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     // 0 is interpreted by TopUpKeyPool() as the default keypool size given by -keypool
     unsigned int kpSize = 0;
     if (params.size() > 0) {
@@ -1663,6 +1712,8 @@ Value walletpassphrase(const Array& params, bool fHelp)
             + HelpExampleRpc("walletpassphrase", "\"my pass phrase\", 60")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     if (fHelp)
         return true;
     if (!pwalletMain->IsCrypted())
@@ -1710,6 +1761,8 @@ Value walletpassphrasechange(const Array& params, bool fHelp)
             + HelpExampleRpc("walletpassphrasechange", "\"old one\", \"new one\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     if (fHelp)
         return true;
     if (!pwalletMain->IsCrypted())
@@ -1756,6 +1809,8 @@ Value walletlock(const Array& params, bool fHelp)
             + HelpExampleRpc("walletlock", "")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     if (fHelp)
         return true;
     if (!pwalletMain->IsCrypted())
@@ -1797,6 +1852,8 @@ Value encryptwallet(const Array& params, bool fHelp)
             + HelpExampleRpc("encryptwallet", "\"my pass phrase\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     if (fHelp)
         return true;
     if (pwalletMain->IsCrypted())
@@ -1861,6 +1918,8 @@ Value lockunspent(const Array& params, bool fHelp)
             + HelpExampleRpc("lockunspent", "false, \"[{\\\"txid\\\":\\\"a08e6907dbbd3d809776dbfc5d82e371b764ed838b5655e72f463568df1aadf0\\\",\\\"vout\\\":1}]\"")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     if (params.size() == 1)
         RPCTypeCheck(params, boost::assign::list_of(bool_type));
     else
@@ -1930,6 +1989,8 @@ Value listlockunspent(const Array& params, bool fHelp)
             + HelpExampleRpc("listlockunspent", "")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     vector<COutPoint> vOutpts;
     pwalletMain->ListLockedCoins(vOutpts);
 
@@ -1961,6 +2022,8 @@ Value settxfee(const Array& params, bool fHelp)
             + HelpExampleRpc("settxfee", "0.00001")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     // Amount
     CAmount nAmount = 0;
     if (params[0].get_real() != 0.0)
@@ -1992,6 +2055,8 @@ Value getwalletinfo(const Array& params, bool fHelp)
             + HelpExampleRpc("getwalletinfo", "")
         );
 
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
     Object obj;
     obj.push_back(Pair("walletversion", pwalletMain->GetVersion()));
     obj.push_back(Pair("balance",       ValueFromAmount(pwalletMain->GetBalance())));
diff --git a/src/sync.h b/src/sync.h
index 7891e4156..27e80e813 100644
--- a/src/sync.h
+++ b/src/sync.h
@@ -142,6 +142,17 @@ public:
             Enter(pszName, pszFile, nLine);
     }
 
+    CMutexLock(Mutex* pmutexIn, const char* pszName, const char* pszFile, int nLine, bool fTry = false)
+    {
+        if (!pmutexIn) return;
+
+        lock = boost::unique_lock<Mutex>(*pmutexIn, boost::defer_lock);
+        if (fTry)
+            TryEnter(pszName, pszFile, nLine);
+        else
+            Enter(pszName, pszFile, nLine);
+    }
+
     ~CMutexLock()
     {
         if (lock.owns_lock())