diff --git a/ChangeLog b/ChangeLog
index 87c467fa0b..f76aafa2a4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Mar 31 17:17:56 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* proc.c (rb_mod_define_method): consider visibility in define_method.
+	  patch by mashiro <mail AT mashiro.org>.  fix GH-268.
+
 Sun Mar 31 15:40:30 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* win32/configure.bat: try to fix option arguments split by commas and
diff --git a/proc.c b/proc.c
index fe1bbff00d..4596003daf 100644
--- a/proc.c
+++ b/proc.c
@@ -1377,7 +1377,7 @@ rb_mod_define_method(int argc, VALUE *argv, VALUE mod)
 {
     ID id;
     VALUE body;
-    int noex = NOEX_PUBLIC;
+    int noex = (int)rb_vm_cref()->nd_visi;
 
     if (argc == 1) {
 	id = rb_to_id(argv[0]);
@@ -1410,6 +1410,9 @@ rb_mod_define_method(int argc, VALUE *argv, VALUE mod)
 	    }
 	}
 	rb_method_entry_set(mod, id, method->me, noex);
+	if (noex == NOEX_MODFUNC) {
+	    rb_method_entry_set(rb_singleton_class(mod), id, method->me, NOEX_PUBLIC);
+	}
     }
     else if (rb_obj_is_proc(body)) {
 	rb_proc_t *proc;
@@ -1423,6 +1426,9 @@ rb_mod_define_method(int argc, VALUE *argv, VALUE mod)
 	    proc->block.klass = mod;
 	}
 	rb_add_method(mod, id, VM_METHOD_TYPE_BMETHOD, (void *)body, noex);
+	if (noex == NOEX_MODFUNC) {
+	    rb_add_method(rb_singleton_class(mod), id, VM_METHOD_TYPE_BMETHOD, (void *)body, NOEX_PUBLIC);
+	}
     }
     else {
 	/* type error */
diff --git a/test/ruby/test_method.rb b/test/ruby/test_method.rb
index c1dbd9f35f..655fac5d3b 100644
--- a/test/ruby/test_method.rb
+++ b/test/ruby/test_method.rb
@@ -270,6 +270,38 @@ class TestMethod < Test::Unit::TestCase
     assert_equal(:meth, c.new.meth, feature4254)
   end
 
+  def test_define_method_visibility
+    c = Class.new do
+      public
+      define_method(:foo) {:foo}
+      protected
+      define_method(:bar) {:bar}
+      private
+      define_method(:baz) {:baz}
+    end
+
+    assert_equal(true, c.public_method_defined?(:foo))
+    assert_equal(false, c.public_method_defined?(:bar))
+    assert_equal(false, c.public_method_defined?(:baz))
+
+    assert_equal(false, c.protected_method_defined?(:foo))
+    assert_equal(true, c.protected_method_defined?(:bar))
+    assert_equal(false, c.protected_method_defined?(:baz))
+
+    assert_equal(false, c.private_method_defined?(:foo))
+    assert_equal(false, c.private_method_defined?(:bar))
+    assert_equal(true, c.private_method_defined?(:baz))
+
+    m = Module.new do
+      module_function
+      define_method(:foo) {:foo}
+    end
+    assert_equal(true, m.respond_to?(:foo))
+    assert_equal(false, m.public_method_defined?(:foo))
+    assert_equal(false, m.protected_method_defined?(:foo))
+    assert_equal(true, m.private_method_defined?(:foo))
+  end
+
   def test_super_in_proc_from_define_method
     c1 = Class.new {
       def m