diff --git a/extras_mongoengine/fields.py b/extras_mongoengine/fields.py
index 5871ddf..05b7eb4 100644
--- a/extras_mongoengine/fields.py
+++ b/extras_mongoengine/fields.py
@@ -18,6 +18,8 @@ def to_mongo(self, value):
         return self.prepare_query_value(None, value)
 
     def to_python(self, value):
+        if isinstance(value, timedelta):
+            return value
         return timedelta(seconds=value)
 
     def prepare_query_value(self, op, value):
diff --git a/tests/test_fields.py b/tests/test_fields.py
index 8011b0f..a6d3b15 100644
--- a/tests/test_fields.py
+++ b/tests/test_fields.py
@@ -15,9 +15,18 @@ def total_seconds(self):
         raise AttributeError
 
 class TimedeltaFieldTestCase(unittest.TestCase):
+
     def setUp(self):
+        connect(db='extrasmongoenginetest')
+        self.db = get_db()
         self.field = TimedeltaField()
 
+    def tearDown(self):
+        for collection in self.db.collection_names():
+            if 'system.' in collection:
+                continue
+            self.db.drop_collection(collection)
+
     def test_construct(self):
         self.assertIsInstance(self.field, TimedeltaField)
 
@@ -29,6 +38,21 @@ def test_total_seconds_26(self):
         value = OldStyleTimedelta(minutes=1, seconds=10)
         self.assertEqual(self.field.total_seconds(value), 70)
 
+    def test_number_initialization(self):
+        class Doc(Document):
+            time = TimedeltaField()
+
+        doc = Doc(time=3600).save()
+        self.assertEqual(doc.time, timedelta(hours=1))
+
+    def test_timedelta_initialization(self):
+        class Doc(Document):
+            time = TimedeltaField()
+
+        test_time = timedelta(days=2)
+        doc = Doc(time=test_time).save()
+        self.assertEqual(doc.time, test_time)
+
 class LowerStringFieldTestCase(unittest.TestCase):
 
     def setUp(self):