diff --git a/src/calibre/ebooks/metadata/__init__.py b/src/calibre/ebooks/metadata/__init__.py
index 09632d7bee..9be40f9b49 100644
--- a/src/calibre/ebooks/metadata/__init__.py
+++ b/src/calibre/ebooks/metadata/__init__.py
@@ -16,7 +16,7 @@ from calibre import relpath
 _author_pat = re.compile(',?\s+and\s+', re.IGNORECASE)
 def string_to_authors(raw):
     raw = _author_pat.sub('&', raw)
-    raw = raw.replace('&&', u'\uffff').replace(',', '&')
+    raw = raw.replace('&&', u'\uffff')
     authors = [a.strip().replace(u'\uffff', '&') for a in raw.split('&')]
     return authors