diff --git a/Lib/urllib.py b/Lib/urllib.py
index 494f578ec60..5449104bf7a 100644
--- a/Lib/urllib.py
+++ b/Lib/urllib.py
@@ -369,7 +369,7 @@ def open_https(self, url, data=None):
                 h.putheader('Content-length', '%d' % len(data))
             else:
                 h.putrequest('GET', selector)
-            if auth: h.putheader('Authorization: Basic %s' % auth)
+            if auth: h.putheader('Authorization', 'Basic %s' % auth)
             if realhost: h.putheader('Host', realhost)
             for args in self.addheaders: h.putheader(*args)
             h.endheaders()