diff --git a/src/python/dm/common/processing/plugins/gridftpFileTransferPlugin.py b/src/python/dm/common/processing/plugins/gridftpFileTransferPlugin.py
index dc6c5740b33aca1b21f97e830e581bdeb71bd319..c9c3f32486e6195210d134e9cf208299e0116f22 100755
--- a/src/python/dm/common/processing/plugins/gridftpFileTransferPlugin.py
+++ b/src/python/dm/common/processing/plugins/gridftpFileTransferPlugin.py
@@ -69,7 +69,7 @@ class GridftpFileTransferPlugin(FileTransferPlugin):
             # Check size
             fSize = filePathDict.get('fileSize') 
             sfSize = storageFilePathDict.get('fileSize') 
-            if not fSize or not sfSize or fSize != sfSize:
+            if fSize is None or sfSize is None or fSize != sfSize:
                 # Sizes differ, need to transfer file
                 continue