Index: core/src/main/java/quickfix/SessionState.java
===================================================================
--- core/src/main/java/quickfix/SessionState.java	(revision 923)
+++ core/src/main/java/quickfix/SessionState.java	(working copy)
@@ -105,7 +105,8 @@
 
     public boolean isHeartBeatNeeded() {
         long millisSinceLastSentTime = SystemTime.currentTimeMillis() - getLastSentTime();
-        return millisSinceLastSentTime >= getHeartBeatMillis() && getTestRequestCounter() == 0;
+        // allow 10 ms leeway since exact comparison causes skipped heartbeats occasionally
+        return millisSinceLastSentTime + 10 > getHeartBeatMillis() && getTestRequestCounter() == 0;
     }
 
     public boolean isInitiator() {