diff --git a/ChangeLog b/ChangeLog
index b8e819d11a..259a8f8ace 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Mon Sep 19 07:54:17 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* object.c (rb_obj_clone): singleton class should be attached
+	  singleton object to.  a patch by Satoshi Shiba <shiba AT rvm.jp>
+	  at [ruby-dev:44460].  [Bug #5274]
+
 Sat Sep 17 23:34:10 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* parse.y (parser_data_type): inherit the core type in ripper so
diff --git a/object.c b/object.c
index 5d21709a5d..3a7265b31d 100644
--- a/object.c
+++ b/object.c
@@ -273,12 +273,17 @@ VALUE
 rb_obj_clone(VALUE obj)
 {
     VALUE clone;
+    VALUE singleton;
 
     if (rb_special_const_p(obj)) {
         rb_raise(rb_eTypeError, "can't clone %s", rb_obj_classname(obj));
     }
     clone = rb_obj_alloc(rb_obj_class(obj));
-    RBASIC(clone)->klass = rb_singleton_class_clone(obj);
+    singleton = rb_singleton_class_clone(obj);
+    RBASIC(clone)->klass = singleton;
+    if (FL_TEST(singleton, FL_SINGLETON)) {
+	rb_singleton_class_attached(singleton, clone);
+    }
     RBASIC(clone)->flags = (RBASIC(obj)->flags | FL_TEST(clone, FL_TAINT) | FL_TEST(clone, FL_UNTRUSTED)) & ~(FL_FREEZE|FL_FINALIZE|FL_MARK);
     init_copy(clone, obj);
     rb_funcall(clone, id_init_clone, 1, obj);
diff --git a/test/ruby/test_class.rb b/test/ruby/test_class.rb
index 55940a8891..12f78ddabc 100644
--- a/test/ruby/test_class.rb
+++ b/test/ruby/test_class.rb
@@ -258,4 +258,12 @@ class TestClass < Test::Unit::TestCase
     END
     assert_equal(42, PrivateClass.new.foo)
   end
+
+  StrClone = String.clone
+  Class.new(StrClone)
+
+  def test_cloned_class
+    bug5274 = StrClone.new("[ruby-dev:44460]")
+    assert_equal(bug5274, Marshal.load(Marshal.dump(bug5274)))
+  end
 end