diff --git a/ChangeLog b/ChangeLog
index d8f31d1ec8..2a3ce97ab3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sat Aug 13 09:26:24 2011  Aaron Patterson <aaron@tenderlovemaking.com>
+
+	* ext/psych/lib/psych/core_ext.rb: Make Kernel#y private.
+	  [ruby-core:38913]
+	* test/psych/test_yaml.rb: corresponding test.
+
 Sat Aug 13 09:05:16 2011  Tadayoshi Funaba  <tadf@dotrb.org>
 
 	* ext/date/date_core.c (date_strftime_alloc): followed the change
diff --git a/ext/psych/lib/psych/core_ext.rb b/ext/psych/lib/psych/core_ext.rb
index be26b2f449..2ad75e1661 100644
--- a/ext/psych/lib/psych/core_ext.rb
+++ b/ext/psych/lib/psych/core_ext.rb
@@ -36,4 +36,5 @@ module Kernel
   end
   remove_method :y rescue nil
   alias y psych_y
+  private :y
 end
diff --git a/test/psych/test_yaml.rb b/test/psych/test_yaml.rb
index 41bb377143..807c058d2e 100644
--- a/test/psych/test_yaml.rb
+++ b/test/psych/test_yaml.rb
@@ -3,6 +3,7 @@
 # $Id$
 #
 require 'psych/helper'
+require 'ostruct'
 
 # [ruby-core:01946]
 module Psych_Tests
@@ -14,6 +15,12 @@ class Psych_Unit_Tests < Psych::TestCase
         Psych.domain_types.clear
     end
 
+    def test_y_method
+      assert_raises(NoMethodError) do
+        OpenStruct.new.y 1
+      end
+    end
+
     def test_syck_compat
       time = Time.utc(2010, 10, 10)
       yaml = Psych.dump time