diff --git a/ChangeLog b/ChangeLog
index f13688ec18..5df3c64ad5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Jun 12 12:04:09 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* array.c (rb_ary_uniq_bang): must not be modified once frozen even in
+	  a callback method.
+
 Wed Jun 12 12:03:43 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* array.c (rb_ary_sort_bang): must not be modified once frozen even in
diff --git a/array.c b/array.c
index 9bdbe78d5c..f3076d7cf3 100644
--- a/array.c
+++ b/array.c
@@ -3981,6 +3981,7 @@ rb_ary_uniq_bang(VALUE ary)
 	if (RARRAY_LEN(ary) == (i = RHASH_SIZE(hash))) {
 	    return Qnil;
 	}
+	rb_ary_modify(ary);
 	ARY_SET_LEN(ary, 0);
 	if (ARY_SHARED_P(ary) && !ARY_EMBED_P(ary)) {
 	    rb_ary_unshare(ary);
diff --git a/test/ruby/test_array.rb b/test/ruby/test_array.rb
index 49628215b5..6807598054 100644
--- a/test/ruby/test_array.rb
+++ b/test/ruby/test_array.rb
@@ -1569,6 +1569,15 @@ class TestArray < Test::Unit::TestCase
     assert_equal(nil, b)
   end
 
+  def test_uniq_bang_with_freeze
+    ary = [1,2]
+    orig = ary.dup
+    assert_raise(RuntimeError, "frozen during comparison") {
+      ary.uniq! {|v| ary.freeze; 1}
+    }
+    assert_equal(orig, ary, "must not be modified once frozen")
+  end
+
   def test_unshift
     a = @cls[]
     assert_equal(@cls['cat'], a.unshift('cat'))