diff --git a/ChangeLog b/ChangeLog
index 132a817c0b..be7ca57e5a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sun Nov  6 00:25:11 2016  Sho Hashimoto  <sho.hsmt@gmail.com>
+
+	* enumerator.c (InitVM_Enumerator): Enumerator::Lazy#chunk_while
+	  defined.  [Fix GH-1186]
+	  https://github.com/ruby/ruby/pull/1186
+
 Sun Nov  6 00:22:51 2016  Kazuki Tsujimoto  <kazuki@callcc.net>
 
 	* vm_eval.c (vm_call0_cfunc_with_frame): pass method id to
diff --git a/enumerator.c b/enumerator.c
index 75caa11169..9de08d7d2a 100644
--- a/enumerator.c
+++ b/enumerator.c
@@ -2379,6 +2379,7 @@ InitVM_Enumerator(void)
     rb_define_method(rb_cLazy, "slice_before", lazy_super, -1);
     rb_define_method(rb_cLazy, "slice_after", lazy_super, -1);
     rb_define_method(rb_cLazy, "slice_when", lazy_super, -1);
+    rb_define_method(rb_cLazy, "chunk_while", lazy_super, -1);
     rb_define_method(rb_cLazy, "uniq", lazy_uniq, 0);
 
     rb_define_alias(rb_cLazy, "force", "to_a");