diff --git a/taiga/projects/attachments/serializers.py b/taiga/projects/attachments/serializers.py
index e772c5e8..46ba0b97 100644
--- a/taiga/projects/attachments/serializers.py
+++ b/taiga/projects/attachments/serializers.py
@@ -21,7 +21,9 @@ from django.conf import settings
 
 from rest_framework import serializers
 
+from taiga.base.serializers import ModelSerializer
 from taiga.base.utils.urls import reverse
+
 from . import models
 
 
@@ -30,6 +32,8 @@ class AttachmentSerializer(serializers.ModelSerializer):
     url = serializers.SerializerMethodField("get_url")
     size = serializers.SerializerMethodField("get_size")
 
+    attached_file = serializers.FileField(required=True)
+
     class Meta:
         model = models.Attachment
         fields = ("id", "project", "owner", "name", "attached_file", "size", "url",