diff --git a/ChangeLog b/ChangeLog
index 6e829ade40..0d294d2d03 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sat Oct 24 13:38:45 2009  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* object.c (rb_obj_cmp): defines Object#<=>.  [ruby-core:24063]
+
 Sat Oct 24 00:36:47 2009  Tanaka Akira  <akr@fsij.org>
 
 	* io.c (io_cntl): update max file descriptor by the result of
diff --git a/lib/delegate.rb b/lib/delegate.rb
index 9ce3aee81e..77804e47ff 100644
--- a/lib/delegate.rb
+++ b/lib/delegate.rb
@@ -115,7 +115,7 @@
 # implementation, see SimpleDelegator.
 #
 class Delegator
-  [:to_s,:inspect,:=~,:!~,:===].each do |m|
+  [:to_s,:inspect,:=~,:!~,:===,:<=>].each do |m|
     undef_method m
   end
 
diff --git a/object.c b/object.c
index 6e69343732..9f7537f12b 100644
--- a/object.c
+++ b/object.c
@@ -1119,6 +1119,15 @@ rb_obj_not_match(VALUE obj1, VALUE obj2)
 }
 
 
+/* :nodoc: */
+static VALUE
+rb_obj_cmp(VALUE obj1, VALUE obj2)
+{
+    if (obj1 == obj2 || rb_obj_equal(obj1, obj2))
+	return INT2FIX(0);
+    return Qnil;
+}
+
 /***********************************************************************
  *
  * Document-class: Module
@@ -2555,6 +2564,7 @@ Init_Object(void)
     rb_define_method(rb_mKernel, "!~", rb_obj_not_match, 1);
     rb_define_method(rb_mKernel, "eql?", rb_obj_equal, 1);
     rb_define_method(rb_mKernel, "hash", rb_obj_hash, 0);
+    rb_define_method(rb_mKernel, "<=>", rb_obj_cmp, 1);
 
     rb_define_method(rb_mKernel, "class", rb_obj_class, 0);
     rb_define_method(rb_mKernel, "clone", rb_obj_clone, 0);