diff --git a/ChangeLog b/ChangeLog
index 1e96d2e36b..d65842e99c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Wed Nov 28 15:31:11 2012  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* io.c (FMODE_SYNCWRITE): removed unused macro.
+
 Wed Nov 28 15:19:25 2012  Naohisa Goto  <ngotogenome@gmail.com>
 
 	* configure.in: revert r37911, r37906 and r37904 which break build
diff --git a/io.c b/io.c
index b89b87b29f..cab47d08b0 100644
--- a/io.c
+++ b/io.c
@@ -727,8 +727,6 @@ flush_before_seek(rb_io_t *fptr)
 # define SEEK_END 2
 #endif
 
-#define FMODE_SYNCWRITE (FMODE_SYNC|FMODE_WRITABLE)
-
 void
 rb_io_check_char_readable(rb_io_t *fptr)
 {