diff --git a/ChangeLog b/ChangeLog
index 57b30b8a6a..c0b7d37478 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sat May 14 22:45:28 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* missing/setproctitle.c: add to include "ruby/util.h".
+
 Sat May 14 19:52:22 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* test/ruby/test_rubyoptions.rb (TestRubyOptions#test_set_program_name):
diff --git a/missing/setproctitle.c b/missing/setproctitle.c
index 8922d58ab6..a9b4fbe825 100644
--- a/missing/setproctitle.c
+++ b/missing/setproctitle.c
@@ -33,6 +33,7 @@
  */
 
 #include "ruby.h"
+#include "ruby/util.h"
 
 #ifndef HAVE_SETPROCTITLE