diff --git a/ChangeLog b/ChangeLog
index 2032f7bde5..720af5015a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Oct  7 00:27:58 2006  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* class.c (rb_include_module): remove unnecessary check.
+	  [ruby-talk:218402]
+
 Fri Oct  6 15:19:59 2006  Akinori MUSHA  <knu@iDaemons.org>
 
 	* ext/digest/depend: Fix header installation when the build
diff --git a/class.c b/class.c
index 81956e5feb..c204fdd41b 100644
--- a/class.c
+++ b/class.c
@@ -352,9 +352,6 @@ rb_include_module(VALUE klass, VALUE module)
 	rb_secure(4);
     }
     
-    if (NIL_P(module)) return;
-    if (klass == module) return;
-
     if (TYPE(module) != T_MODULE) {
 	Check_Type(module, T_MODULE);
     }