diff --git a/ChangeLog b/ChangeLog
index 299b5ccae2..c1b43629f9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Jul 15 10:56:01 2013  Zachary Scott  <e@zzak.io>
+
+	* thread.c (mutex_sleep): [DOC] Awake thread will reacquire lock
+	  By Tim Abdulla [Fixes GH-342] https://github.com/ruby/ruby/pull/342
+
 Mon Jul 15 10:45:09 2013  Tanaka Akira  <akr@fsij.org>
 
 	* bignum.c (nlz16): Use __builtin_clz if possible.
diff --git a/thread.c b/thread.c
index babec1f51e..eaf408fa6d 100644
--- a/thread.c
+++ b/thread.c
@@ -4562,6 +4562,9 @@ rb_mutex_sleep(VALUE self, VALUE timeout)
  * non-nil or forever.  Raises +ThreadError+ if +mutex+ wasn't locked by
  * the current thread.
  *
+ * When the thread is next woken up, it will attempt to reacquire
+ * the lock.
+ *
  * Note that this method can wakeup without explicit Thread#wakeup call.
  * For example, receiving signal and so on.
  */