diff --git a/S3/Config.py b/S3/Config.py
index 6568a16e..58ecafc3 100644
--- a/S3/Config.py
+++ b/S3/Config.py
@@ -272,7 +272,8 @@ def __init__(self, configfile = None, access_key=None, secret_key=None, access_t
                     self.aws_credential_file()
 
             # override these if passed on the command-line
-            if access_key and secret_key:
+            # Allow blank secret_key
+            if access_key and secret_key is not None:
                 self.access_key = access_key
                 self.secret_key = secret_key
             if access_token: