diff --git a/lib/interfax/object.rb b/lib/interfax/object.rb
index 043bee4..5f064eb 100644
--- a/lib/interfax/object.rb
+++ b/lib/interfax/object.rb
@@ -1,3 +1,5 @@
+require "ostruct"
+
 class InterFAX::Object < OpenStruct
   def attributes
     hash = to_h