diff --git a/src/omero/util/pydict_text_io.py b/src/omero/util/pydict_text_io.py
index 97b76f122..a89901e72 100644
--- a/src/omero/util/pydict_text_io.py
+++ b/src/omero/util/pydict_text_io.py
@@ -47,7 +47,7 @@ def load(fileobj, filetype=None, single=True, session=None):
     :param session: If fileobj is an OriginalFile:ID a valid session is required
     """
 
-    if not isinstance(fileobj, str):
+    if not isinstance(fileobj, (str, bytes)):
         raise Exception(
             'Invalid type: fileobj must be a filename or json string')