diff --git a/README.rdoc b/README.rdoc
index 2e8403c6..f6be8452 100644
--- a/README.rdoc
+++ b/README.rdoc
@@ -804,7 +804,9 @@ enable it yourself:
 When using <tt>send_file</tt> or static files you may have mime types Sinatra
 doesn't understand. Use +mime_type+ to register them by file extension:
 
-  mime_type :foo, 'text/foo'
+  configure do
+    mime_type :foo, 'text/foo'
+  end
 
 You can also use it with the +content_type+ helper: