diff --git a/lib/block/merkleblock.js b/lib/block/merkleblock.js
index 60068f7..311adcf 100644
--- a/lib/block/merkleblock.js
+++ b/lib/block/merkleblock.js
@@ -6,6 +6,7 @@ var BufferReader = require('../encoding/bufferreader');
 var BufferWriter = require('../encoding/bufferwriter');
 var Hash = require('../crypto/hash');
 var JSUtil = require('../util/js');
+var Transaction = require('../transaction');
 var $ = require('../util/preconditions');
 
 /**
@@ -139,6 +140,8 @@ MerkleBlock.prototype.toJSON = function toJSON() {
  * @returns {Bool} - True/False whether this MerkleBlock is Valid
  */
 MerkleBlock.prototype.validMerkleTree = function validMerkleTree() {
+  $.checkState(this.flags instanceof Array, 'MerkleBlock flags is not an array');
+  $.checkState(this.hashes instanceof Array, 'MerkleBlock flags is not an array');
   var self = this;
   if(this._validMerkleTree === true) {
     return true;
@@ -207,6 +210,26 @@ MerkleBlock.prototype.validMerkleTree = function validMerkleTree() {
   }
 }
 
+/**
+ * @param {Transaction|String} - Transaction or Transaction ID Hash
+ * @returns {Bool} - return true/false if this MerkleBlock has the TX or not
+ * @private
+ */
+MerkleBlock.prototype.hasTransaction = function hasTransaction(tx) {
+  $.checkArgument(!_.isUndefined(tx), 'No transaction given');
+  $.checkArgument(tx instanceof Transaction
+    || typeof tx === 'string', 'No transaction given');
+
+  var hash = tx;
+  if(tx instanceof Transaction) {
+    hash = tx.id;
+  }
+  var revHash = BufferUtil.reverse(new Buffer(hash,'hex')).toString('hex');
+
+  return (this.hashes.indexOf(hash) !== -1
+    || this.hashes.indexOf(revHash) !== -1);
+}
+
 /**
  * @param {Bool} - set the merkle tree validity
  * @returns {Bool} - return true/false
diff --git a/test/data/merkleblocks.js b/test/data/merkleblocks.js
index 33aadc8..b6bff4d 100644
--- a/test/data/merkleblocks.js
+++ b/test/data/merkleblocks.js
@@ -1,8 +1,14 @@
 'use strict';
 
 module.exports = {
+  TXHEX: [
+    [ // From Mainnet Block 100014
+      // From: http://btc.blockr.io/api/v1/tx/raw/652b0aa4cf4f17bdb31f7a1d308331bba91f3b3cbf8f39c9cb5e19d4015b9f01
+      "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"
+    ],
+  ],
   HEX: [
-    // Mainnet Block 100015
+    // Mainnet Block 100014
     "01000000" + // Version
       "82bb869cf3a793432a66e826e05a6fc37469f8efb7421dc88067010000000000" + // prevHash
       "7f16c5962e8bd963659c793ce370d95f093bc7e367117b3c30c1f8fdd0d97287" + // MerkleRoot
@@ -19,7 +25,7 @@ module.exports = {
       "1d" // Flags
   ],
   JSON: [
-    { // Mainnet Block 100015
+    { // Mainnet Block 100014
       header: {
         version: 1,
         prevHash: "82bb869cf3a793432a66e826e05a6fc37469f8efb7421dc88067010000000000",
@@ -54,100 +60,13 @@ module.exports = {
     },
     { // Mainnet Block 280472
       flags : [
-        255,
-        85,
-        218,
-        225,
-        90,
-        173,
-        229,
-        43,
-        183,
-        195,
-        213,
-        229,
-        43,
-        108,
-        43,
-        219,
-        226,
-        215,
-        217,
-        226,
-        61,
-        92,
-        253,
-        92,
-        237,
-        134,
-        215,
-        170,
-        174,
-        182,
-        170,
-        237,
-        220,
-        251,
-        106,
-        235,
-        109,
-        109,
-        253,
-        219,
-        58,
-        159,
-        182,
-        221,
-        190,
-        189,
-        181,
-        126,
-        251,
-        223,
-        223,
-        254,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        255,
-        15
+        255, 85, 218, 225, 90, 173, 229, 43, 183, 195, 213, 229, 43, 108, 43,
+        219, 226, 215, 217, 226, 61, 92, 253, 92, 237, 134, 215, 170, 174, 182,
+        170, 237, 220, 251, 106, 235, 109, 109, 253, 219, 58, 159, 182, 221,
+        190, 189, 181, 126, 251, 223, 223, 254, 255, 255, 255, 255, 255, 255,
+        255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+        255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+        255, 255, 255, 255, 255, 255, 255, 15
       ],
       numTransactions : 1159,
       hashes : [
diff --git a/test/merkleblock.js b/test/merkleblock.js
index d2069f7..8b1a506 100644
--- a/test/merkleblock.js
+++ b/test/merkleblock.js
@@ -1,10 +1,13 @@
 'use strict';
-
 var bitcore = require('..');
 var MerkleBlock = bitcore.MerkleBlock;
 var BufferReader = bitcore.encoding.BufferReader;
 var BufferWriter = bitcore.encoding.BufferWriter;
+var BufferUtil = bitcore.util.buffer;
+var Transaction = bitcore.Transaction;
 var data = require('./data/merkleblocks.js');
+var transactionVector = require('./data/tx_creation');
+
 
 describe('MerkleBlock', function() {
   var blockhex  = data.HEX[0];
@@ -139,8 +142,53 @@ describe('MerkleBlock', function() {
       });
     });
 
+    it('should not validate merkleblocks with too many hashes', function() {
+      var json = data.JSON[0];
+      var b = MerkleBlock(JSON.stringify(data.JSON[0]));
+      // Add too many hashes
+      var i = 0;
+      while(i <= b.numTransactions) {
+        b.hashes.push('bad' + i++);
+      }
+      b.validMerkleTree().should.equal(false);
+    });
+
+    it('should not validate merkleblocks with too few bit flags', function() {
+      var json = JSON.stringify(data.JSON[0]);
+      var b = MerkleBlock(json);
+      b.flags.pop()
+      b.validMerkleTree().should.equal(false);
+    });
+
   });
 
+  describe('#hasTransaction', function() {
+
+    it('should find transactions via hash string', function() {
+      var json = data.JSON[0];
+      var txId = BufferUtil.reverse(new Buffer(json.hashes[1],'hex')).toString('hex');
+      var b = MerkleBlock(JSON.stringify(json));
+      b.hasTransaction(txId).should.equal(true);
+      b.hasTransaction(txId + 'abcd').should.equal(false);
+    });
+
+    it('should find transactions via Transaction object', function() {
+      var json = data.JSON[0];
+      var txBuf = new Buffer(data.TXHEX[0][0],'hex');
+      var tx = new Transaction().fromBuffer(txBuf);
+      var b = MerkleBlock(JSON.stringify(json));
+      b.hasTransaction(tx).should.equal(true);
+    });
+
+    it('should not find non-existant Transaction object', function() {
+      // Reuse another transaction already in data/ dir
+      var serialized = transactionVector[0][7];
+      var tx = new Transaction().fromBuffer(new Buffer(serialized, 'hex'));
+      var b = MerkleBlock(JSON.stringify(data.JSON[0]));
+      b.hasTransaction(tx).should.equal(false);
+    });
+
+  });
 
 });