diff --git a/django/core/signing.py b/django/core/signing.py
index 054777a260..3165cf8a38 100644
--- a/django/core/signing.py
+++ b/django/core/signing.py
@@ -158,8 +158,12 @@ class Signer(object):
 
 
 class TimestampSigner(Signer):
+    def __init__(self, *args, **kwargs):
+        self.time_func = kwargs.pop('time', time.time)
+        super(TimestampSigner, self).__init__(*args, **kwargs)
+    
     def timestamp(self):
-        return baseconv.base62.encode(int(time.time()))
+        return baseconv.base62.encode(int(self.time_func() * 10000))
 
     def sign(self, value):
         value = smart_str('%s%s%s' % (value, self.sep, self.timestamp()))
@@ -168,10 +172,10 @@ class TimestampSigner(Signer):
     def unsign(self, value, max_age=None):
         result =  super(TimestampSigner, self).unsign(value)
         value, timestamp = result.rsplit(self.sep, 1)
-        timestamp = baseconv.base62.decode(timestamp)
+        timestamp = baseconv.base62.decode(timestamp) / 10000.0
         if max_age is not None:
             # Check timestamp is not older than max_age
-            age = time.time() - timestamp
+            age = self.time_func() - timestamp
             if age > max_age:
                 raise SignatureExpired(
                     'Signature age %s > %s seconds' % (age, max_age))
diff --git a/tests/regressiontests/signing/tests.py b/tests/regressiontests/signing/tests.py
index 0b0cacf10e..bc16214600 100644
--- a/tests/regressiontests/signing/tests.py
+++ b/tests/regressiontests/signing/tests.py
@@ -1,5 +1,3 @@
-import time
-
 from django.core import signing
 from django.test import TestCase
 from django.utils.encoding import force_unicode
@@ -98,19 +96,21 @@ class TestTimestampSigner(TestCase):
 
     def test_timestamp_signer(self):
         value = u'hello'
-        _time = time.time
-        time.time = lambda: 123456789
-        try:
-            signer = signing.TimestampSigner('predictable-key')
-            ts = signer.sign(value)
-            self.assertNotEqual(ts,
-                signing.Signer('predictable-key').sign(value))
+        signer = signing.TimestampSigner('predictable-key',
+            time=lambda: 123456789)
+        ts = signer.sign(value)
+        self.assertNotEqual(ts,
+            signing.Signer('predictable-key').sign(value))
 
-            self.assertEqual(signer.unsign(ts), value)
-            time.time = lambda: 123456800
-            self.assertEqual(signer.unsign(ts, max_age=12), value)
-            self.assertEqual(signer.unsign(ts, max_age=11), value)
-            self.assertRaises(
-                signing.SignatureExpired, signer.unsign, ts, max_age=10)
-        finally:
-            time.time = _time
+        self.assertEqual(signer.unsign(ts), value)
+        signer = signing.TimestampSigner('predictable-key',
+            time=lambda: 123456800)
+        self.assertEqual(signer.unsign(ts, max_age=12), value)
+        self.assertEqual(signer.unsign(ts, max_age=11), value)
+        self.assertRaises(
+            signing.SignatureExpired, signer.unsign, ts, max_age=10)
+    
+    def test_timestamp_precision(self):
+        one = signing.TimestampSigner('key', time=lambda: 123.4567).sign('v')
+        two = signing.TimestampSigner('key', time=lambda: 123.4568).sign('v')
+        self.assertNotEqual(one, two)