diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4434195e..6795515d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Fixed
+
+- Fix missing timestamp value in old grafana API endpoint ([#3522](https://github.com/grafana/oncall/pull/3522))
+
 ## v1.3.73 (2023-12-06)
 
 ### Added
diff --git a/engine/apps/integrations/tests/test_views.py b/engine/apps/integrations/tests/test_views.py
index 7cfaa61a..79e28049 100644
--- a/engine/apps/integrations/tests/test_views.py
+++ b/engine/apps/integrations/tests/test_views.py
@@ -184,6 +184,46 @@ def test_integration_grafana_endpoint_has_alerts(
     )
 
 
+@patch("apps.integrations.views.create_alert")
+@pytest.mark.django_db
+def test_integration_old_grafana_endpoint(
+    mock_create_alert, settings, make_organization_and_user, make_alert_receive_channel
+):
+    settings.DEBUG = False
+
+    integration_type = "grafana"
+    organization, user = make_organization_and_user()
+    alert_receive_channel = make_alert_receive_channel(
+        organization=organization,
+        author=user,
+        integration=integration_type,
+    )
+
+    client = APIClient()
+    url = reverse("integrations:grafana", kwargs={"alert_channel_key": alert_receive_channel.token})
+
+    data = {}
+    now = timezone.now()
+    with patch("django.utils.timezone.now") as mock_now:
+        mock_now.return_value = now
+        response = client.post(url, data, format="json")
+    assert response.status_code == status.HTTP_200_OK
+
+    mock_create_alert.apply_async.assert_called_once_with(
+        [],
+        {
+            "title": "Title",
+            "message": None,
+            "image_url": None,
+            "link_to_upstream_details": None,
+            "alert_receive_channel_pk": alert_receive_channel.pk,
+            "integration_unique_data": '{"evalMatches": []}',
+            "raw_request_data": data,
+            "received_at": now.isoformat(),
+        },
+    )
+
+
 @patch("apps.integrations.views.create_alert")
 @pytest.mark.parametrize(
     "integration_type",
diff --git a/engine/apps/integrations/views.py b/engine/apps/integrations/views.py
index 05ea76f3..b2f9d5c0 100644
--- a/engine/apps/integrations/views.py
+++ b/engine/apps/integrations/views.py
@@ -289,6 +289,7 @@ class GrafanaAPIView(
                 },
             )
         else:
+            timestamp = timezone.now().isoformat()
             create_alert.apply_async(
                 [],
                 {