diff --git a/ChangeLog b/ChangeLog
index 7da0d9377d..eec0c1bf35 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sun Feb 24 21:15:05 2013  Tadayoshi Funaba  <tadf@dotrb.org>
+
+	* ext/date/date_core.c: [ruby-core:52303]
+
 Sun Feb 24 15:33:46 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* random.c (rb_random_ulong_limited): limit is inclusive, but generic
diff --git a/ext/date/date_core.c b/ext/date/date_core.c
index 37d00d177e..f898c46aa2 100644
--- a/ext/date/date_core.c
+++ b/ext/date/date_core.c
@@ -7765,7 +7765,7 @@ datetime_s_now(int argc, VALUE *argv, VALUE klass)
     of = tm.tm_gmtoff;
 #elif defined(HAVE_VAR_TIMEZONE)
 #ifdef HAVE_VAR_ALTZONE
-    of = (long)((tm.tm_isdst > 0) ? altzone : timezone);
+    of = (long)-((tm.tm_isdst > 0) ? altzone : timezone);
 #else
     of = (long)-timezone;
     if (tm.tm_isdst) {