diff --git a/lib/ansible/cli/__init__.py b/lib/ansible/cli/__init__.py
index 4dc565461f..6d219e54f8 100644
--- a/lib/ansible/cli/__init__.py
+++ b/lib/ansible/cli/__init__.py
@@ -177,7 +177,7 @@ class CLI(object):
             self.options.become_method = 'sudo'
         elif self.options.su:
             self.options.become = True
-            options.become_method = 'su'
+            self.options.become_method = 'su'
 
 
     def validate_conflicts(self, vault_opts=False, runas_opts=False):