diff --git a/lib/sawyer/serializer.rb b/lib/sawyer/serializer.rb
index b711de4..c799de3 100644
--- a/lib/sawyer/serializer.rb
+++ b/lib/sawyer/serializer.rb
@@ -23,7 +23,11 @@ def self.json
 
     def self.multi_json
       require 'multi_json'
-      new(MultiJson)
+      if defined?(MultiJSON)
+        new(MultiJSON, :generate, :parse)
+      else
+        new(MultiJson)
+      end
     rescue LoadError
     end