diff -r de35eae9048a Lib/queue.py
--- a/Lib/queue.py	Wed Apr 24 23:33:20 2013 +0200
+++ b/Lib/queue.py	Thu Apr 25 20:58:20 2013 +0100
@@ -6,6 +6,7 @@
     import dummy_threading as threading
 from collections import deque
 from heapq import heappush, heappop
+from itertools import count
 try:
     from time import monotonic as time
 except ImportError:
@@ -220,17 +221,21 @@
     Entries are typically tuples of the form:  (priority number, data).
     '''
 
-    def _init(self, maxsize):
+    def _init(self, maxsize, key=None):
         self.queue = []
+        if key is None:
+            key = lambda x: x
+        self.key = key
+        self.counter = count()
 
     def _qsize(self):
         return len(self.queue)
 
     def _put(self, item):
-        heappush(self.queue, item)
+        heappush(self.queue, (self.key(item), next(self.counter), item))
 
     def _get(self):
-        return heappop(self.queue)
+        return heappop(self.queue)[2]
 
 
 class LifoQueue(Queue):
diff -r de35eae9048a Lib/test/test_queue.py
--- a/Lib/test/test_queue.py	Wed Apr 24 23:33:20 2013 +0200
+++ b/Lib/test/test_queue.py	Thu Apr 25 20:58:20 2013 +0100
@@ -354,6 +354,37 @@
         self.failing_queue_test(q)
 
 
+class TestKeyedPriorityQueue(unittest.TestCase):
+    def test_key(self):
+        q = PriorityQueue(key=len)
+        q.put([1, 2, 3, 4])
+        q.put([5, 6])
+        q.put([7, 8, 9])
+        self.assertEqual(q.get(), [5, 6])
+        self.assertEqual(q.get(), [7, 8, 9])
+        self.assertEqual(q.get(), [1, 2, 3, 4])
+
+    def test_lifo_within_equal_priority(self):
+        test_items = [10, 19, 14, 12, 17, 15, 16, 5, 4,
+                     2, 18, 11, 13, 0, 1, 3, 7, 6, 8, 9]
+        expected_order = [5, 4, 2, 0, 1, 3, 7, 6, 8, 9,
+                          10, 19, 14, 12, 17, 15, 16, 18, 11, 13]
+        q = PriorityQueue(key=lambda n: n // 10)
+        for item in test_items:
+            q.put([item])
+        for item in expected_order:
+            self.assertEqual(q.get(), item)
+
+    def test_unorderable_items(self):
+        q = PriorityQueue(key=abs)
+        q.put(3 + 4j)
+        q.put(1j)
+        q.put(5 + 12j)
+        self.assertEqual(q.get(), 1j)
+        self.assertEqual(q.get(), 3 + 4j)
+        self.assertEqual(q.get(), 5 + 12j)
+
+
 def test_main():
     support.run_unittest(QueueTest, LifoQueueTest, PriorityQueueTest,
                               FailingQueueTest)