diff --git a/src/test/miner_tests.cpp b/src/test/miner_tests.cpp
index 8001c4f65..46c9ae021 100644
--- a/src/test/miner_tests.cpp
+++ b/src/test/miner_tests.cpp
@@ -57,6 +57,8 @@ BOOST_AUTO_TEST_CASE(CreateNewBlock_validity)
     CScript script;
     uint256 hash;
 
+    LOCK(cs_main);
+
     // Simple block creation, nothing special yet:
     BOOST_CHECK(pblocktemplate = CreateNewBlockWithKey(reservekey));