diff --git a/ChangeLog b/ChangeLog
index ce8676a3b7..1481bc064d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Thu Apr 14 14:58:14 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/tk/tkutil/tkutil.c (tk_hash_kv): the third argument can be
+	  nil not only an Array.  reported by @windwiny at
+	  https://github.com/ruby/ruby/commit/cdaa94e#commitcomment-17096618
+
 Thu Apr 14 14:28:55 2016  cremno phobia  <cremno@mail.ru>
 
 	* cont.c (fiber_initialize_machine_stack_context): fix wrong
diff --git a/ext/tk/tkutil/tkutil.c b/ext/tk/tkutil/tkutil.c
index 3b1d3c5ecf..249ed57448 100644
--- a/ext/tk/tkutil/tkutil.c
+++ b/ext/tk/tkutil/tkutil.c
@@ -804,7 +804,7 @@ tk_hash_kv(argc, argv, self)
     switch(argc) {
     case 3:
         ary = argv[2];
-	Check_Type(ary, T_ARRAY);
+	if (!NIL_P(ary)) Check_Type(ary, T_ARRAY);
     case 2:
         enc_flag = argv[1];
     case 1: