diff --git a/ChangeLog b/ChangeLog
index 70c5cf05a7..432996cab1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Dec 18 09:44:47 2015  SHIBATA Hiroshi  <hsbt@ruby-lang.org>
+
+	* ext/pty/pty.c: fix double words typo.
+	  [ci skip][fix GH-1157] Patch by @jwworth
+
 Fri Dec 18 09:42:45 2015  SHIBATA Hiroshi  <hsbt@ruby-lang.org>
 
 	* ext/nkf/nkf-utf8/utf8tbl.c: fix a typo.
diff --git a/ext/pty/pty.c b/ext/pty/pty.c
index 34421f288b..c8aee4ce38 100644
--- a/ext/pty/pty.c
+++ b/ext/pty/pty.c
@@ -579,7 +579,7 @@ pty_detach_process(struct pty_info *info)
  *
  * In the block form these same values will be yielded to the block:
  *
- * +r+:: A readable IO that that contains the command's
+ * +r+:: A readable IO that contains the command's
  *       standard output and standard error
  * +w+:: A writable IO that is the command's standard input
  * +pid+:: The process identifier for the command.