diff --git a/django/forms/fields.py b/django/forms/fields.py
index 45cc8185c0dc1..4cd2911eaad46 100644
--- a/django/forms/fields.py
+++ b/django/forms/fields.py
@@ -340,11 +340,13 @@ def to_python(self, value):
                     return self.strptime(value, format)
                 except ValueError:
                     if format.endswith('.%f'):
-                        if value.count('.') != 1:
+                        # Compatibility with datetime in pythons < 2.6.
+                        # See: http://docs.python.org/library/datetime.html#strftime-and-strptime-behavior
+                        if value.count('.') != format.count('.'):
                             continue
                         try:
                             datetime_str, usecs_str = value.rsplit('.', 1)
-                            usecs = int(usecs_str)
+                            usecs = int(usecs_str[:6].ljust(6, '0'))
                             dt = datetime.datetime.strptime(datetime_str, format[:-3])
                             return dt.replace(microsecond=usecs)
                         except ValueError:
diff --git a/tests/regressiontests/forms/tests/fields.py b/tests/regressiontests/forms/tests/fields.py
index dd55c9011110c..0f9e91a55e4f9 100644
--- a/tests/regressiontests/forms/tests/fields.py
+++ b/tests/regressiontests/forms/tests/fields.py
@@ -407,6 +407,7 @@ def test_datetimefield_1(self):
         self.assertEqual(datetime.datetime(2006, 10, 25, 14, 30, 59), f.clean(datetime.datetime(2006, 10, 25, 14, 30, 59)))
         self.assertEqual(datetime.datetime(2006, 10, 25, 14, 30, 59, 200), f.clean(datetime.datetime(2006, 10, 25, 14, 30, 59, 200)))
         self.assertEqual(datetime.datetime(2006, 10, 25, 14, 30, 45, 200), f.clean('2006-10-25 14:30:45.000200'))
+        self.assertEqual(datetime.datetime(2006, 10, 25, 14, 30, 45, 200), f.clean('2006-10-25 14:30:45.0002'))
         self.assertEqual(datetime.datetime(2006, 10, 25, 14, 30, 45), f.clean('2006-10-25 14:30:45'))
         self.assertEqual(datetime.datetime(2006, 10, 25, 14, 30), f.clean('2006-10-25 14:30:00'))
         self.assertEqual(datetime.datetime(2006, 10, 25, 14, 30), f.clean('2006-10-25 14:30'))
@@ -452,6 +453,9 @@ def test_datetimefield_4(self):
         self.assertEqual(datetime.datetime(2006, 10, 25, 0, 0), f.clean(' 10/25/06 '))
         self.assertRaisesMessage(ValidationError, "[u'Enter a valid date/time.']", f.clean, '   ')
 
+    def test_datetimefield_5(self):
+        f = DateTimeField(input_formats=[u'%Y.%m.%d %H:%M:%S.%f'])
+        self.assertEqual(datetime.datetime(2006, 10, 25, 14, 30, 45, 200), f.clean('2006.10.25 14:30:45.0002'))
     # RegexField ##################################################################
 
     def test_regexfield_1(self):