diff --git a/ChangeLog b/ChangeLog
index c0e7c13ff8..c925fb1bf6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Jan  1 23:17:49 2010  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* lib/uri/generic.rb (URI#normalize!): normalize case of
+	  scheme. [ruby-core:27309]
+
 Fri Jan  1 00:47:57 2010  Akinori MUSHA  <knu@iDaemons.org>
 
 	* ext/digest/digest.c (rb_digest_instance_method_unimpl): Suppress
diff --git a/lib/uri/generic.rb b/lib/uri/generic.rb
index 1ca970de74..14ca97301b 100644
--- a/lib/uri/generic.rb
+++ b/lib/uri/generic.rb
@@ -992,6 +992,9 @@ module URI
       if path && path == ''
         set_path('/')
       end
+      if scheme && scheme != scheme.downcase
+        set_scheme(self.scheme.downcase)
+      end
       if host && host != host.downcase
         set_host(self.host.downcase)
       end