diff --git a/lib/iruby/backend.rb b/lib/iruby/backend.rb
index e08909b..b6a79d6 100644
--- a/lib/iruby/backend.rb
+++ b/lib/iruby/backend.rb
@@ -1,6 +1,5 @@
 module IRuby
   In, Out = [nil], [nil]
-  ::In, ::Out = In, Out
 
   module History
     def eval(code, store_history)