diff --git a/lib/guard/phpunit/runner.rb b/lib/guard/phpunit/runner.rb
index 83bde28..1a9022b 100644
--- a/lib/guard/phpunit/runner.rb
+++ b/lib/guard/phpunit/runner.rb
@@ -46,7 +46,7 @@ def run(paths, options = {})
         # @return [Boolean] The status of phpunit
         #
         def phpunit_exists?
-          system('which phpunit > /dev/null 2>&1')
+          system('hash', 'phpunit')
         end
 
         # Executes the testing command on the tests