diff --git a/gunicorn/app/base.py b/gunicorn/app/base.py
index 3a027013..da69f2f7 100644
--- a/gunicorn/app/base.py
+++ b/gunicorn/app/base.py
@@ -6,6 +6,7 @@
 import logging
 import optparse
 import os
+import traceback
 
 from gunicorn import __version__
 from gunicorn import util