diff --git a/requests/auth.py b/requests/auth.py
index bd2fe7d8..701104d0 100644
--- a/requests/auth.py
+++ b/requests/auth.py
@@ -12,6 +12,7 @@ import re
 import time
 import hashlib
 import threading
+import warnings
 
 from base64 import b64encode
 
@@ -36,9 +37,23 @@ def _basic_auth_str(username, password):
     # These are here solely to maintain backwards compatibility
     # for things like ints. This will be removed in 3.0.0.
     if not isinstance(username, basestring):
+        warnings.warn(
+            "Non-string usernames will no longer be supported in Requests "
+            "3.0.0. Please convert the object you've passed in ({!r}) to "
+            "a string or bytes object in the near future to avoid "
+            "problems.".format(username),
+            category=DeprecationWarning,
+        )
         username = str(username)
 
     if not isinstance(password, basestring):
+        warnings.warn(
+            "Non-string passwords will no longer be supported in Requests "
+            "3.0.0. Please convert the object you've passed in ({!r}) to "
+            "a string or bytes object in the near future to avoid "
+            "problems.".format(password),
+            category=DeprecationWarning,
+        )
         password = str(password)
     # -- End Removal --
 
diff --git a/tests/test_requests.py b/tests/test_requests.py
index b94e0fa2..70564d26 100755
--- a/tests/test_requests.py
+++ b/tests/test_requests.py
@@ -514,7 +514,8 @@ class TestRequests:
         'username, password', (
             ('user', 'pass'),
             (u'имя'.encode('utf-8'), u'пароль'.encode('utf-8')),
-            (42, 42)
+            (42, 42),
+            (None, None),
         ))
     def test_set_basicauth(self, httpbin, username, password):
         auth = (username, password)