--- a/src/bitcoinrpc.cpp
+++ b/src/bitcoinrpc.cpp
@@ -2913,10 +2913,15 @@
     StopRequests();
 }
 
+static CCriticalSection cs_THREAD_RPCHANDLER;
+
 void ThreadRPCServer3(void* parg)
 {
     IMPLEMENT_RANDOMIZE_STACK(ThreadRPCServer3(parg));
-    vnThreadsRunning[THREAD_RPCHANDLER]++;
+    {
+        LOCK(cs_THREAD_RPCHANDLER);
+        vnThreadsRunning[THREAD_RPCHANDLER]++;
+    }
     AcceptedConnection *conn = (AcceptedConnection *) parg;
 
     bool fRun = true;
@@ -2925,7 +2930,10 @@
         {
             conn->close();
             delete conn;
-            --vnThreadsRunning[THREAD_RPCHANDLER];
+            {
+                LOCK(cs_THREAD_RPCHANDLER);
+                --vnThreadsRunning[THREAD_RPCHANDLER];
+            }
             return;
         }
         map<string, string> mapHeaders;
@@ -3005,7 +3013,10 @@
     }
 
     delete conn;
-    vnThreadsRunning[THREAD_RPCHANDLER]--;
+    {
+        LOCK(cs_THREAD_RPCHANDLER);
+        vnThreadsRunning[THREAD_RPCHANDLER]--;
+    }
 }
 
 json_spirit::Value CRPCTable::execute(const std::string &strMethod, const json_spirit::Array &params) const