diff --git a/ChangeLog b/ChangeLog
index 00b38f4b30..42d0967085 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+Fri Nov  2 17:52:12 2012  Shugo Maeda  <shugo@ruby-lang.org>
+
+	* object.c (rb_mod_to_s): Module#{to_s,inspect}, when invoked on
+	  a refinement, returns a string in the format #<refinement:C@M>,
+	  where C is a refined class and M is a module at which the refinemet
+	  is defined.
+	
+	* eval.c (rb_mod_refine): store information on a refinement for the
+	  above change.
+
+	* test/ruby/test_refinement.rb: related test.
+
 Fri Nov  2 16:57:52 2012  Shota Fukumori  <sorah@tubusu.net>
 
 	* vm_dump.c (rb_vm_bugreport): Because of many log directories,
diff --git a/eval.c b/eval.c
index 08d20d2204..21c33137f0 100644
--- a/eval.c
+++ b/eval.c
@@ -1218,7 +1218,7 @@ rb_mod_refine(VALUE module, VALUE klass)
 {
     NODE *cref = rb_vm_cref();
     VALUE mod;
-    ID id_refinements, id_refined_class;
+    ID id_refinements, id_refined_class, id_defined_at;
     VALUE refinements;
 
     if (!rb_block_given_p()) {
@@ -1236,6 +1236,8 @@ rb_mod_refine(VALUE module, VALUE klass)
 	mod = rb_module_new();
 	CONST_ID(id_refined_class, "__refined_class__");
 	rb_ivar_set(mod, id_refined_class, klass);
+	CONST_ID(id_defined_at, "__defined_at__");
+	rb_ivar_set(mod, id_defined_at, module);
 	rb_define_singleton_method(mod, "method_added",
 				   refinement_module_method_added, 1);
 	rb_define_singleton_method(mod, "include",
diff --git a/object.c b/object.c
index f3e5ec241b..1b020beaa3 100644
--- a/object.c
+++ b/object.c
@@ -1336,6 +1336,9 @@ rb_obj_cmp(VALUE obj1, VALUE obj2)
 static VALUE
 rb_mod_to_s(VALUE klass)
 {
+    ID id_refined_class, id_defined_at;
+    VALUE refined_class, defined_at;
+
     if (FL_TEST(klass, FL_SINGLETON)) {
 	VALUE s = rb_usascii_str_new2("#<");
 	VALUE v = rb_iv_get(klass, "__attached__");
@@ -1353,6 +1356,19 @@ rb_mod_to_s(VALUE klass)
 
 	return s;
     }
+    CONST_ID(id_refined_class, "__refined_class__");
+    refined_class = rb_attr_get(klass, id_refined_class);
+    if (!NIL_P(refined_class)) {
+	VALUE s = rb_usascii_str_new2("#<refinement:");
+
+	rb_str_concat(s, rb_inspect(refined_class));
+	rb_str_cat2(s, "@");
+	CONST_ID(id_defined_at, "__defined_at__");
+	defined_at = rb_attr_get(klass, id_defined_at);
+	rb_str_concat(s, rb_inspect(defined_at));
+	rb_str_cat2(s, ">");
+	return s;
+    }
     return rb_str_dup(rb_class_name(klass));
 }
 
diff --git a/test/ruby/test_refinement.rb b/test/ruby/test_refinement.rb
index 4a0e6d1327..eee66105b1 100644
--- a/test/ruby/test_refinement.rb
+++ b/test/ruby/test_refinement.rb
@@ -622,4 +622,28 @@ class TestRefinement < Test::Unit::TestCase
   def test_symbol_to_proc
     assert_equal("foo", SymbolToProc::M.call_foo)
   end
+
+  module Inspect
+    module M
+      refine Fixnum do
+      end
+    end
+  end
+
+  def test_inspect
+    assert_equal("#<refinement:Fixnum@TestRefinement::Inspect::M>",
+                 Inspect::M.refinements[Fixnum].inspect)
+
+    c = Class.new
+    m = Module.new {
+      refine String do
+      end
+      refine c do
+      end
+    }
+    assert_equal("#<refinement:String@#{m.inspect}>",
+                 m.refinements[String].inspect)
+    assert_equal("#<refinement:#{c.inspect}@#{m.inspect}>",
+                 m.refinements[c].inspect)
+  end
 end