diff --git a/bson/json_util.py b/bson/json_util.py
index 983573edc..925897e94 100644
--- a/bson/json_util.py
+++ b/bson/json_util.py
@@ -48,7 +48,13 @@ instances (as they are extended strings you can't provide custom defaults),
 but it will be faster as there is less recursion.
 
 .. versionchanged:: 2.8
-   Supports $numberLong and $undefined - new in MongoDB 2.6. Also supports
+   The output format for :class:`~bson.timestamp.Timestamp` has changed from
+   '{"t": <int>, "i": <int>}' to '{"$timestamp": {"t": <int>, "i": <int>}}'.
+   This new format will be decoded to an instance of
+   :class:`~bson.timestamp.Timestamp`. The old format will continue to be
+   decoded to a python dict as before. Encoding to the old format is no longer
+   supported as it was never correct and loses type information.
+   Added support for $numberLong and $undefined - new in MongoDB 2.6 - and
    parsing $date in ISO-8601 format.
 
 .. versionchanged:: 2.7
@@ -232,6 +238,9 @@ def object_hook(dct, compile_re=True):
         # 2to3 will change this to int. PyMongo 3.0 supports
         # a new type, Int64, to avoid round trip issues.
         return long(dct["$numberLong"])
+    if "$timestamp" in dct:
+        tsp = dct["$timestamp"]
+        return Timestamp(tsp["t"], tsp["i"])
     return dct
 
 
@@ -279,7 +288,7 @@ def default(obj):
     if isinstance(obj, MaxKey):
         return {"$maxKey": 1}
     if isinstance(obj, Timestamp):
-        return SON([("t", obj.time), ("i", obj.inc)])
+        return {"$timestamp": SON([("t", obj.time), ("i", obj.inc)])}
     if isinstance(obj, Code):
         return SON([('$code', str(obj)), ('$scope', obj.scope)])
     if isinstance(obj, Binary):
diff --git a/doc/changelog.rst b/doc/changelog.rst
index 1ff913f6e..35d00b882 100644
--- a/doc/changelog.rst
+++ b/doc/changelog.rst
@@ -30,6 +30,13 @@ Highlights include:
   - :meth:`~pymongo.mongo_client.MongoClient.copy_database`
   - :class:`~pymongo.master_slave_connection.MasterSlaveConnection`
 
+  The JSON format for :class:`~bson.timestamp.Timestamp` has changed from
+  '{"t": <int>, "i": <int>}' to '{"$timestamp": {"t": <int>, "i": <int>}}'.
+  This new format will be decoded to an instance of
+  :class:`~bson.timestamp.Timestamp`. The old format will continue to be
+  decoded to a python dict as before. Encoding to the old format is no
+  longer supported as it was never correct and loses type information.
+
 Issues Resolved
 ...............
 
diff --git a/test/test_json_util.py b/test/test_json_util.py
index 861cf02d0..8b6a7dd94 100644
--- a/test/test_json_util.py
+++ b/test/test_json_util.py
@@ -177,14 +177,14 @@ class TestJsonUtil(unittest.TestCase):
         self.round_trip({"m": MaxKey()})
 
     def test_timestamp(self):
-        res = json_util.dumps({"ts": Timestamp(4, 13)}, default=json_util.default)
+        dct = {"ts": Timestamp(4, 13)}
+        res = json_util.dumps(dct, default=json_util.default)
         if not PY24:
             # Check order.
-            self.assertEqual('{"ts": {"t": 4, "i": 13}}', res)
+            self.assertEqual('{"ts": {"$timestamp": {"t": 4, "i": 13}}}', res)
 
-        dct = json_util.loads(res)
-        self.assertEqual(dct['ts']['t'], 4)
-        self.assertEqual(dct['ts']['i'], 13)
+        rtdct = json_util.loads(res)
+        self.assertEqual(dct, rtdct)
 
     def test_uuid(self):
         if not bson.has_uuid():