diff --git a/letsencrypt/crypto_util.py b/letsencrypt/crypto_util.py
index 1007f18c7..2f24c4fb6 100644
--- a/letsencrypt/crypto_util.py
+++ b/letsencrypt/crypto_util.py
@@ -4,7 +4,6 @@
     is capable of handling the signatures.
 
 """
-import datetime
 import logging
 import os