diff --git a/ChangeLog b/ChangeLog
index 9332f21943..3c60c9cfec 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sun Mar  1 02:30:23 2015  Seiei Higa  <hanachin@gmail.com>
+
+	* vm_method.c (rb_alias): raise a NameError when creating alias to
+	  a refined method if the original method of the refined method is
+	  not defined.  [ruby-core:67523] [Bug #10731]
+
 Sun Mar  1 01:17:24 2015  Seiei Higa  <hanachin@gmail.com>
 
 	* vm_method.c (rb_export_method): bail out if the original method
diff --git a/test/ruby/test_refinement.rb b/test/ruby/test_refinement.rb
index 65137f0e3a..98bf9c6027 100644
--- a/test/ruby/test_refinement.rb
+++ b/test/ruby/test_refinement.rb
@@ -1181,6 +1181,31 @@ class TestRefinement < Test::Unit::TestCase
     end;
   end
 
+  def test_alias_refined_method
+    assert_separately([], <<-"end;")
+    bug10731 = '[ruby-core:67523] [Bug #10731]'
+
+    class C
+    end
+
+    module RefinementBug
+      refine C do
+        def foo
+        end
+
+        def bar
+        end
+      end
+    end
+
+    assert_raise(NameError, bug10731) do
+      class C
+        alias foo bar
+      end
+    end
+    end;
+  end
+
   private
 
   def eval_using(mod, s)
diff --git a/version.h b/version.h
index 02f9f18a28..d70d742f46 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.1.5"
 #define RUBY_RELEASE_DATE "2015-03-01"
-#define RUBY_PATCHLEVEL 304
+#define RUBY_PATCHLEVEL 305
 
 #define RUBY_RELEASE_YEAR 2015
 #define RUBY_RELEASE_MONTH 3
diff --git a/vm_method.c b/vm_method.c
index 08946b9862..3748e92679 100644
--- a/vm_method.c
+++ b/vm_method.c
@@ -1259,7 +1259,9 @@ rb_alias(VALUE klass, ID name, ID def)
   again:
     orig_me = search_method(klass, def, &defined_class);
 
-    if (UNDEFINED_METHOD_ENTRY_P(orig_me)) {
+    if (UNDEFINED_METHOD_ENTRY_P(orig_me) ||
+	(orig_me->def->type == VM_METHOD_TYPE_REFINED &&
+	 UNDEFINED_METHOD_ENTRY_P(orig_me->def->body.orig_me))) {
 	if ((!RB_TYPE_P(klass, T_MODULE)) ||
 	    (orig_me = search_method(rb_cObject, def, 0),
 	     UNDEFINED_METHOD_ENTRY_P(orig_me))) {