diff --git a/ChangeLog b/ChangeLog
index fe243578ea..8f4d1b4466 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Sep  4 00:17:55 2016  Sho Hashimoto  <sho-h@ruby-lang.org>
+
+	* proc.c: [DOC] fix Object#define_singleton_method and
+	  main.define_method return value. [ci skip]
+
 Sat Sep  3 11:28:29 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* thread_pthread.c (ruby_init_stack): check stack bounds even if
diff --git a/proc.c b/proc.c
index 8d3f62b1fe..c096f62739 100644
--- a/proc.c
+++ b/proc.c
@@ -1932,8 +1932,8 @@ rb_mod_define_method(int argc, VALUE *argv, VALUE mod)
 
 /*
  *  call-seq:
- *     define_singleton_method(symbol, method) -> new_method
- *     define_singleton_method(symbol) { block } -> proc
+ *     define_singleton_method(symbol, method) -> symbol
+ *     define_singleton_method(symbol) { block } -> symbol
  *
  *  Defines a singleton method in the receiver. The _method_
  *  parameter can be a +Proc+, a +Method+ or an +UnboundMethod+ object.
@@ -1965,8 +1965,8 @@ rb_obj_define_method(int argc, VALUE *argv, VALUE obj)
 }
 
 /*
- *     define_method(symbol, method)     -> new_method
- *     define_method(symbol) { block }   -> proc
+ *     define_method(symbol, method)     -> symbol
+ *     define_method(symbol) { block }   -> symbol
  *
  *  Defines a global function by _method_ or the block.
  */