diff --git a/src/replication.c b/src/replication.c
index 2042389d..348428c5 100644
--- a/src/replication.c
+++ b/src/replication.c
@@ -1421,6 +1421,10 @@ void replicationCron(void) {
             redisLog(REDIS_NOTICE,"MASTER <-> SLAVE sync started");
         }
     }
+
+    /* Send ACK to master from time to time. */
+    if (server.masterhost && server.master)
+        replicationSendAck();
     
     /* If we have attached slaves, PING them from time to time.
      * So slaves can implement an explicit timeout to masters, and will