diff --git a/Gemfile b/Gemfile
index dfef7ae91..14d844eba 100644
--- a/Gemfile
+++ b/Gemfile
@@ -60,7 +60,7 @@ group :test, :development do
   gem 'factory_girl_rails', :require => false
   gem 'ruby-debug-base19', '0.11.23' if RUBY_VERSION.include? '1.9.1'
   gem 'ruby-debug19' if RUBY_VERSION.include? '1.9'
-  gem 'ruby-debug' if RUBY_VERSION.include? '1.8'
+  gem 'ruby-debug' if defined?(Rubinius).nil? && RUBY_VERSION.include?('1.8')
   gem 'launchy'
 end