diff --git a/actionpack/lib/action_view/helpers/text_helper.rb b/actionpack/lib/action_view/helpers/text_helper.rb
index 46af3012d9..3bc5afc2c4 100644
--- a/actionpack/lib/action_view/helpers/text_helper.rb
+++ b/actionpack/lib/action_view/helpers/text_helper.rb
@@ -263,7 +263,7 @@ module ActionView
       #
       #   post_body = "Welcome to my new blog at http://www.myblog.com/.  Please e-mail me at me@email.com."
       #   auto_link(post_body, :html => { :target => '_blank' }) do |text|
-      #     truncate(text, 15)
+      #     truncate(text, :length => 15)
       #   end
       #   # => "Welcome to my new blog at <a href=\"http://www.myblog.com/\" target=\"_blank\">http://www.m...</a>.
       #         Please e-mail me at <a href=\"mailto:me@email.com\">me@email.com</a>."