diff --git a/ChangeLog b/ChangeLog
index b7dea226f1..5698062c42 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -5,6 +5,8 @@ Tue Sep 16 18:28:52 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* io.c (rb_io_readlines, rb_f_gets): ditto.
 
+	* io.c (rb_io_readbyte): rdoc updated.  [ruby-core:18617]
+
 Tue Sep 16 11:55:16 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* string.c (rb_str_each_codepoint): add new methods, #codepoints
diff --git a/io.c b/io.c
index 56745aa685..cab6d7f2ff 100644
--- a/io.c
+++ b/io.c
@@ -2748,7 +2748,7 @@ rb_io_getbyte(VALUE io)
  *  call-seq:
  *     ios.readbyte   => fixnum
  *
- *  Reads a character as with <code>IO#getc</code>, but raises an
+ *  Reads a byte as with <code>IO#getbyte</code>, but raises an
  *  <code>EOFError</code> on end of file.
  */