Index: Lib/urllib/request.py
===================================================================
--- Lib/urllib/request.py	(revision 82895)
+++ Lib/urllib/request.py	(revision )
@@ -1591,13 +1591,13 @@
 
         if proxy_passwd:
             import base64
-            proxy_auth = base64.b64encode(proxy_passwd).strip()
+            proxy_auth = base64.b64encode(proxy_passwd.encode()).strip()
         else:
             proxy_auth = None
 
         if user_passwd:
             import base64
-            auth = base64.b64encode(user_passwd).strip()
+            auth = base64.b64encode(user_passwd.encode()).strip()
         else:
             auth = None
         http_conn = connection_factory(host)
Index: Lib/test/test_urllib.py
===================================================================
--- Lib/test/test_urllib.py	(revision 82983)
+++ Lib/test/test_urllib.py	(revision )
@@ -190,6 +190,13 @@
         finally:
             self.unfakehttp()
 
+    def test_username_password(self):
+        self.fakehttp(b'Hello!')
+        try:
+            urlopen('http://username:password@google.com/index.html')
+        finally:
+            self.unfakehttp()
+
 class urlretrieve_FileTests(unittest.TestCase):
     """Test urllib.urlretrieve() on local files"""