diff --git a/lib/fog/compute/rackspace.rb b/lib/fog/compute/rackspace.rb
index d706e7844..f376c7a45 100644
--- a/lib/fog/compute/rackspace.rb
+++ b/lib/fog/compute/rackspace.rb
@@ -58,6 +58,7 @@ module Fog
         end
 
         def initialize(options={})
+          require 'json'
           @rackspace_username = options[:rackspace_username]
         end