diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index 4c2064261..7bed4ab87 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -351,9 +351,8 @@ class ManyRelatedMixin(object):
         except:
             # Non-form data
             value = data.get(self.source or field_name)
-        else:
-            if value == ['']:
-                value = []
+        if value == [''] or value is None:
+            value = []
         into[field_name] = [self.from_native(item) for item in value]
 
 
diff --git a/rest_framework/tests/serializer.py b/rest_framework/tests/serializer.py
index 7d750b813..38117b36c 100644
--- a/rest_framework/tests/serializer.py
+++ b/rest_framework/tests/serializer.py
@@ -342,11 +342,10 @@ class ManyToManyTests(TestCase):
         serializer = self.serializer_class(data=data)
         self.assertEqual(serializer.is_valid(), True)
         instance = serializer.save()
-        self.assertEquals(len(ManyToManyModel.objects.all()), 3)
-        self.assertEquals(instance.pk, 3)
+        self.assertEquals(len(ManyToManyModel.objects.all()), 2)
+        self.assertEquals(instance.pk, 2)
         self.assertEquals(list(instance.rel.all()), [])
 
-
     def test_create_empty_relationship_flat_data(self):
         """
         Create an instance of a model with a ManyToMany relationship,