diff --git a/ChangeLog b/ChangeLog
index fd7f1b3625..5d5a7ae07e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Wed Oct 22 17:25:17 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* io.c (pipe_open): remove unnecessary flush before fork.
+	  a patch from Kazuhiro NISHIYAMA <zn at mbf.nifty.com>
+	  in [ruby-dev:36840].
+
 Wed Oct 22 16:27:57 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* vm_insnhelper.c (vm_yield_setup_args): should not drop arguments
diff --git a/io.c b/io.c
index bf893faaab..bfeefef432 100644
--- a/io.c
+++ b/io.c
@@ -4445,8 +4445,6 @@ pipe_open(struct rb_exec_arg *eargp, VALUE prog, const char *modestr, int fmode,
     }
     else {
 	fflush(stdin);		/* is it really needed? */
-	rb_io_flush(rb_stdout);
-	rb_io_flush(rb_stderr);
 	pid = rb_fork(&status, 0, 0, Qnil);
 	if (pid == 0) {		/* child */
 	    popen_redirect(&arg);