diff --git a/taiga/projects/api.py b/taiga/projects/api.py
index ad41a173..5f5532f8 100644
--- a/taiga/projects/api.py
+++ b/taiga/projects/api.py
@@ -242,7 +242,7 @@ class MembershipViewSet(ModelCrudViewSet):
         return Response(status=status.HTTP_204_NO_CONTENT)
 
     def pre_delete(self, obj):
-        if not services.can_user_leave_project(obj.user, obj.project):
+        if obj.user is not None and not services.can_user_leave_project(obj.user, obj.project):
             raise exc.BadRequest(_("At least one of the user must be an active admin"))
 
     def pre_save(self, obj):
diff --git a/tests/integration/test_memberships.py b/tests/integration/test_memberships.py
index a77013e4..90fd1e97 100644
--- a/tests/integration/test_memberships.py
+++ b/tests/integration/test_memberships.py
@@ -184,3 +184,14 @@ def test_api_delete_membership(client):
     response = client.json.delete(url)
 
     assert response.status_code == 204
+
+
+def test_api_delete_membership_without_user(client):
+    membership_owner = f.MembershipFactory(is_owner=True)
+    membership_without_user_one = f.MembershipFactory(project=membership_owner.project, user=None)
+    membership_without_user_two = f.MembershipFactory(project=membership_owner.project, user=None)
+    client.login(membership_owner.user)
+    url = reverse("memberships-detail", args=[membership_without_user_one.id])
+    response = client.json.delete(url)
+
+    assert response.status_code == 204