Index: Lib/subprocess.py
===================================================================
--- Lib/subprocess.py	(revision 81951)
+++ Lib/subprocess.py	(working copy)
@@ -577,7 +577,7 @@
         if result:
             result.append(' ')
 
-        needquote = (" " in arg) or ("\t" in arg) or ("|" in arg) or not arg
+        needquote = (" " in arg) or ("\t" in arg) or ("|" in arg) or ("&" in arg) or not arg
         if needquote:
             result.append('"')
 
Index: Lib/test/test_subprocess.py
===================================================================
--- Lib/test/test_subprocess.py	(revision 81951)
+++ Lib/test/test_subprocess.py	(working copy)
@@ -488,6 +488,8 @@
                          'ab ""')
         self.assertEqual(subprocess.list2cmdline(['echo', 'foo|bar']),
                          'echo "foo|bar"')
+        self.assertEqual(subprocess.list2cmdline(['echo', 'foo&bar']),
+                         'echo "foo&bar"')
 
 
     def test_poll(self):