diff --git a/lib/fog/rackspace.rb b/lib/fog/rackspace.rb
index 15a8211bb..65d7ee472 100644
--- a/lib/fog/rackspace.rb
+++ b/lib/fog/rackspace.rb
@@ -122,7 +122,7 @@ module Fog
 
     def self.json_response?(response)
       return false unless response && response.headers
-      response.headers['Content-Type'] =~ %r{application/json}i ? true : false
+      response.get_header('Content-Type') =~ %r{application/json}i ? true : false
     end
 
     def self.normalize_url(endpoint)