diff -r 1043cc2cb0ff Lib/test/test_urllib.py
--- a/Lib/test/test_urllib.py	Sat Sep 07 15:24:01 2013 +0300
+++ b/Lib/test/test_urllib.py	Sun Sep 15 23:24:37 2013 +0300
@@ -1068,11 +1068,11 @@
 
     def test_nonstring_values(self):
         self.assertEqual("a=1", urllib.parse.urlencode({"a": 1}))
-        self.assertEqual("a=None", urllib.parse.urlencode({"a": None}))
+        self.assertEqual("a", urllib.parse.urlencode({"a": None}))
 
     def test_nonstring_seq_values(self):
         self.assertEqual("a=1&a=2", urllib.parse.urlencode({"a": [1, 2]}, True))
-        self.assertEqual("a=None&a=a",
+        self.assertEqual("a&a=a",
                          urllib.parse.urlencode({"a": [None, "a"]}, True))
         data = collections.OrderedDict([("a", 1), ("b", 1)])
         self.assertEqual("a=a&a=b",
diff -r 1043cc2cb0ff Lib/urllib/parse.py
--- a/Lib/urllib/parse.py	Sat Sep 07 15:24:01 2013 +0300
+++ b/Lib/urllib/parse.py	Sun Sep 15 23:24:37 2013 +0300
@@ -768,12 +768,15 @@
                 k = quote_plus(k, safe)
             else:
                 k = quote_plus(str(k), safe, encoding, errors)
-
-            if isinstance(v, bytes):
-                v = quote_plus(v, safe)
+            
+            if v is None:
+                l.append(k)
             else:
-                v = quote_plus(str(v), safe, encoding, errors)
-            l.append(k + '=' + v)
+                if isinstance(v, bytes):
+                    v = quote_plus(v, safe)
+                else:
+                    v = quote_plus(str(v), safe, encoding, errors)
+                l.append(k + '=' + v)
     else:
         for k, v in query:
             if isinstance(k, bytes):
@@ -798,6 +801,10 @@
                 else:
                     # loop over the sequence
                     for elt in v:
+                        if elt is None:
+                            l.append(k)
+                            continue
+
                         if isinstance(elt, bytes):
                             elt = quote_plus(elt, safe)
                         else: