diff --git a/taiga/projects/api.py b/taiga/projects/api.py
index 5e47df67..ed7805ec 100644
--- a/taiga/projects/api.py
+++ b/taiga/projects/api.py
@@ -176,9 +176,9 @@ class MembershipViewSet(ModelCrudViewSet):
 
     @list_route(methods=["POST"])
     def bulk_create(self, request, **kwargs):
-        project_id = request.DATA.get('projectId', None)
+        project_id = request.DATA.get('project_id', None)
         if project_id is None:
-            raise exc.BadRequest(_('projectId parameter is mandatory'))
+            raise exc.BadRequest(_('project_id parameter is mandatory'))
 
         bulk_members = request.DATA.get('bulk_memberships', None)
         if bulk_members is None:
diff --git a/tests/integration/test_memberships.py b/tests/integration/test_memberships.py
index 5e737e20..96120923 100644
--- a/tests/integration/test_memberships.py
+++ b/tests/integration/test_memberships.py
@@ -40,7 +40,7 @@ def test_api_create_bulk_members(client):
     url = reverse("memberships-bulk-create")
 
     data = {
-        "projectId": project.id,
+        "project_id": project.id,
         "bulk_memberships": [
             {"role_id": tester.pk, "email": john.email},
             {"role_id": gamer.pk, "email": joseph.email},