diff --git a/ChangeLog b/ChangeLog
index fc8659cf6d..932972cf57 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7340,4 +7340,7 @@
 	  Simona (2014-5-14).
 	* arch/arm/src/sam34/sam_gpio.c:  Fix some SAM4E compiler errors when
 	  CONFIG_DEBUG_GPIO is enabled (2014-5-15).
+	* sched/sig_mqnotempty.c:  Test for a valid signal number is inverted; this
+	  function could not have been working correctly???  From eero.nurkkala
+	  (2014-5-20).
 
diff --git a/sched/sig_mqnotempty.c b/sched/sig_mqnotempty.c
index 54ea2f9aa3..9bdfa9f146 100644
--- a/sched/sig_mqnotempty.c
+++ b/sched/sig_mqnotempty.c
@@ -103,7 +103,7 @@ int sig_mqnotempty(int pid, int signo, void *sival_ptr)
 
   /* Verify that we can perform the signalling operation */
 
-  if (GOOD_SIGNO(signo))
+  if (!GOOD_SIGNO(signo))
     {
       return -EINVAL;
     }