diff --git a/demo/demoproject/storage/tests.py b/demo/demoproject/storage/tests.py
index 1924f48..8536781 100644
--- a/demo/demoproject/storage/tests.py
+++ b/demo/demoproject/storage/tests.py
@@ -1,7 +1,9 @@
+import datetime
 import unittest
 
 from django.core.files.base import ContentFile
 from django.core.urlresolvers import reverse
+from django.http.response import HttpResponseNotModified
 import django.test
 
 from django_downloadview import assert_download_response, temporary_media_root
@@ -31,6 +33,32 @@ class StaticPathTestCase(django.test.TestCase):
                                  basename='1.txt',
                                  mime_type='text/plain')
 
+    @temporary_media_root()
+    def test_not_modified_download_response(self):
+        """'storage:static_path' sends not modified response if unmodified."""
+        setup_file('1.txt')
+        url = reverse('storage:static_path', kwargs={'path': '1.txt'})
+        response = self.client.get(
+            url,
+            HTTP_IF_MODIFIED_SINCE='Sat, 29 Oct {year} 19:43:31 GMT'.format(
+                year=datetime.date.today().year + 4)
+        )
+        self.assertTrue(isinstance(response, HttpResponseNotModified))
+
+    @temporary_media_root()
+    def test_modified_since_download_response(self):
+        """'storage:static_path' streams file if modified."""
+        setup_file('1.txt')
+        url = reverse('storage:static_path', kwargs={'path': '1.txt'})
+        response = self.client.get(
+            url,
+            HTTP_IF_MODIFIED_SINCE='Sat, 29 Oct 1980 19:43:31 GMT')
+        assert_download_response(self,
+                                 response,
+                                 content=file_content,
+                                 basename='1.txt',
+                                 mime_type='text/plain')
+
 
 class DynamicPathIntegrationTestCase(django.test.TestCase):
     """Integration tests around ``storage:dynamic_path`` URL."""
diff --git a/django_downloadview/views/base.py b/django_downloadview/views/base.py
index a8b9c82..29121c3 100644
--- a/django_downloadview/views/base.py
+++ b/django_downloadview/views/base.py
@@ -1,6 +1,8 @@
 # -*- coding: utf-8 -*-
 """Base material for download views: :class:`DownloadMixin` and
 :class:`BaseDownloadView`"""
+import calendar
+
 from django.http import HttpResponseNotModified, Http404
 from django.views.generic.base import View
 from django.views.static import was_modified_since
@@ -111,7 +113,8 @@ class DownloadMixin(object):
             return file_instance.was_modified_since(since)
         except (AttributeError, NotImplementedError):
             try:
-                modification_time = file_instance.modified_time
+                modification_time = calendar.timegm(
+                    file_instance.modified_time.utctimetuple())
                 size = file_instance.size
             except (AttributeError, NotImplementedError):
                 return True
diff --git a/tests/views.py b/tests/views.py
index bfa9aa7..80c6907 100644
--- a/tests/views.py
+++ b/tests/views.py
@@ -2,6 +2,7 @@
 """Tests around :mod:`django_downloadview.views`."""
 import os
 import unittest
+from datetime import datetime
 try:
     from unittest import mock
 except ImportError:
@@ -92,7 +93,7 @@ class DownloadMixinTestCase(unittest.TestCase):
         file_wrapper.was_modified_since = mock.Mock(
             side_effect=AttributeError)
         file_wrapper.size = mock.sentinel.size
-        file_wrapper.modified_time = mock.sentinel.modified_time
+        file_wrapper.modified_time = datetime.now()
         was_modified_since_mock = mock.Mock(
             return_value=mock.sentinel.was_modified)
         mixin = views.DownloadMixin()