diff --git a/ChangeLog b/ChangeLog
index ae1730a48d..6f70211c2b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Mar 17 02:38:21 2013  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* ext/date/date_core.c: include sys/time.h for avoiding implicit
+	  declaration of gettimeofday().
+
 Sun Mar 17 00:55:31 2013  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* include/ruby/missing.h: removed __linux__. it's unnecessary.
diff --git a/ext/date/date_core.c b/ext/date/date_core.c
index 323a4550b2..51fb5c1d83 100644
--- a/ext/date/date_core.c
+++ b/ext/date/date_core.c
@@ -6,6 +6,9 @@
 #include "ruby/encoding.h"
 #include <math.h>
 #include <time.h>
+#if defined(HAVE_SYS_TIME_H)
+#include <sys/time.h>
+#endif
 
 #define NDEBUG
 #include <assert.h>