diff --git a/lib/fastly-rails/client.rb b/lib/fastly-rails/client.rb
index 79122fd..3d35991 100644
--- a/lib/fastly-rails/client.rb
+++ b/lib/fastly-rails/client.rb
@@ -1,4 +1,5 @@
 require 'fastly'
+require 'uri'
 
 module FastlyRails
   # A simple wrapper around the fastly-ruby client.
@@ -13,7 +14,7 @@ def purge_by_key(key)
     end
 
     def purge_url(key)
-      "/service/#{FastlyRails.service_id}/purge/#{key}"
+      "/service/#{FastlyRails.service_id}/purge/#{URI.escape(key)}"
     end
   end
 end