diff --git a/lib/liquid/standardfilters.rb b/lib/liquid/standardfilters.rb
index d67c99d1..3be892aa 100644
--- a/lib/liquid/standardfilters.rb
+++ b/lib/liquid/standardfilters.rb
@@ -46,7 +46,7 @@ module Liquid
     end
 
     def url_decode(input)
-      CGI.unescape(input) rescue input
+      CGI.unescape(input) unless input.nil?
     end
 
     def slice(input, offset, length = nil)