diff --git a/ChangeLog b/ChangeLog
index 061352aca8..52c80b0c39 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Nov 12 01:29:15 2009  Yusuke Endoh  <mame@tsg.ne.jp>
+
+	* enumerator.c (yielder_yield_push): Yielder#<< should return self.
+	  [ruby-dev:39660] 
+
 Wed Nov 11 19:17:35 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* lib/tempfile.rb (Tempfile#initialize): merge mode option.
diff --git a/enumerator.c b/enumerator.c
index e341c07d75..7c50f3dda2 100644
--- a/enumerator.c
+++ b/enumerator.c
@@ -1012,6 +1012,13 @@ yielder_yield(VALUE obj, VALUE args)
     return rb_proc_call(ptr->proc, args);
 }
 
+/* :nodoc: */
+static VALUE yielder_yield_push(VALUE obj, VALUE args)
+{
+    yielder_yield(obj, args);
+    return obj;
+}
+
 static VALUE
 yielder_yield_i(VALUE obj, VALUE memo, int argc, VALUE *argv)
 {
@@ -1228,7 +1235,7 @@ Init_Enumerator(void)
     rb_define_alloc_func(rb_cYielder, yielder_allocate);
     rb_define_method(rb_cYielder, "initialize", yielder_initialize, 0);
     rb_define_method(rb_cYielder, "yield", yielder_yield, -2);
-    rb_define_method(rb_cYielder, "<<", yielder_yield, -2);
+    rb_define_method(rb_cYielder, "<<", yielder_yield_push, -2);
 
     id_rewind = rb_intern("rewind");
     id_each = rb_intern("each");