diff --git a/courses/serializers.py b/courses/serializers.py
index b7010dc..7b2434b 100644
--- a/courses/serializers.py
+++ b/courses/serializers.py
@@ -39,7 +39,7 @@ class LessonSerializer(MiniLessonSerializer):
     @staticmethod
     def get_materials(self):
         try:
-            prefix = 'course/%s/%s/%s' % (self.topic.course.token, self.topic.id, self.token)
+            prefix = 'materials/%s/%s/%s' % (self.topic.course.token, self.topic.id, self.token)
             name_list = os.listdir('%s/%s/' % (settings.MEDIA_ROOT, prefix))
             return ["%s%s/%s" % (settings.MEDIA_URL, prefix, i) for i in name_list]
         except FileNotFoundError: