diff --git a/ChangeLog b/ChangeLog
index 555deb38e8..1392993f89 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,10 @@ Mon Aug  3 13:05:22 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 	* array.c (rb_ary_{permutation,combination,product}): must not use
 	  ary_discard on strings.
 
+Mon Aug  3 06:43:25 2009  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* numeric.c (flo_hash): normalize -0.0 to 0.0.  [ruby-core:24577]
+
 Mon Aug  3 00:32:00 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* random.c (rb_random_int): arguments have to be converted to
diff --git a/numeric.c b/numeric.c
index 3330e26933..57e420bb86 100644
--- a/numeric.c
+++ b/numeric.c
@@ -913,6 +913,8 @@ flo_hash(VALUE num)
     int hash;
 
     d = RFLOAT_VALUE(num);
+    /* normalize -0.0 to 0.0 */
+    if (d == 0.0) d = 0.0;
     hash = rb_memhash(&d, sizeof(d));
     return INT2FIX(hash);
 }