diff --git a/CHANGELOG.md b/CHANGELOG.md
index ca254640..34c4efd2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Fixed too frequent retry of `perform_notification` task on Telegram ratelimit error by @Ferril ([#3744](https://github.com/grafana/oncall/pull/3744))
+- Add check whether organization has Slack connection on update Slack related field using public api endpoints
+  by @Ferril ([#3751](https://github.com/grafana/oncall/pull/3751))
 
 ## v1.3.92 (2024-01-23)
 
diff --git a/engine/apps/public_api/serializers/routes.py b/engine/apps/public_api/serializers/routes.py
index 878722be..0b6468db 100644
--- a/engine/apps/public_api/serializers/routes.py
+++ b/engine/apps/public_api/serializers/routes.py
@@ -86,6 +86,8 @@ class BaseChannelFilterSerializer(OrderedModelSerializer):
             slack_channel_id = slack_channel_id.upper()
             organization = self.context["request"].auth.organization
             slack_team_identity = organization.slack_team_identity
+            if not slack_team_identity:
+                raise BadRequest(detail="Slack isn't connected to this workspace")
             try:
                 slack_team_identity.get_cached_channels().get(slack_id=slack_channel_id)
             except SlackChannel.DoesNotExist:
diff --git a/engine/apps/public_api/serializers/schedules_base.py b/engine/apps/public_api/serializers/schedules_base.py
index 03e4ae60..5ea13cb4 100644
--- a/engine/apps/public_api/serializers/schedules_base.py
+++ b/engine/apps/public_api/serializers/schedules_base.py
@@ -45,6 +45,9 @@ class ScheduleBaseSerializer(serializers.ModelSerializer):
         organization = self.context["request"].auth.organization
         slack_team_identity = organization.slack_team_identity
 
+        if (slack_channel_id or user_group_id) and not slack_team_identity:
+            raise BadRequest(detail="Slack isn't connected to this workspace")
+
         if slack_channel_id is not None:
             slack_channel_id = slack_channel_id.upper()
             try:
diff --git a/engine/apps/public_api/tests/test_integrations.py b/engine/apps/public_api/tests/test_integrations.py
index 0d7a3045..8f9e2473 100644
--- a/engine/apps/public_api/tests/test_integrations.py
+++ b/engine/apps/public_api/tests/test_integrations.py
@@ -819,6 +819,50 @@ def test_update_integration_default_route(
     assert response.data["default_route"]["escalation_chain_id"] == escalation_chain.public_primary_key
 
 
+@pytest.mark.django_db
+def test_create_integration_default_route_with_slack_field(
+    make_organization_and_user_with_token,
+    make_escalation_chain,
+):
+    organization, _, token = make_organization_and_user_with_token()
+    escalation_chain = make_escalation_chain(organization)
+
+    client = APIClient()
+    data_for_create = {
+        "type": "grafana",
+        "name": "grafana_created",
+        "team_id": None,
+        "default_route": {
+            "escalation_chain_id": escalation_chain.public_primary_key,
+            "slack": {"channel_id": "TEST_SLACK_ID"},
+        },
+    }
+    url = reverse("api-public:integrations-list")
+    response = client.post(url, data=data_for_create, format="json", HTTP_AUTHORIZATION=f"{token}")
+    assert response.status_code == status.HTTP_400_BAD_REQUEST
+    assert response.data["detail"] == "Slack isn't connected to this workspace"
+
+
+@pytest.mark.django_db
+def test_update_integration_default_route_with_slack_field(
+    make_organization_and_user_with_token, make_alert_receive_channel, make_channel_filter
+):
+    organization, _, token = make_organization_and_user_with_token()
+    integration = make_alert_receive_channel(organization)
+    make_channel_filter(integration, is_default=True)
+
+    client = APIClient()
+    data_for_update = {
+        "default_route": {"slack": {"channel_id": "TEST_SLACK_ID"}},
+    }
+
+    url = reverse("api-public:integrations-detail", args=[integration.public_primary_key])
+    response = client.put(url, data=data_for_update, format="json", HTTP_AUTHORIZATION=f"{token}")
+
+    assert response.status_code == status.HTTP_400_BAD_REQUEST
+    assert response.data["detail"] == "Slack isn't connected to this workspace"
+
+
 @pytest.mark.django_db
 def test_cant_create_integrations_direct_paging(
     make_organization_and_user_with_token, make_team, make_alert_receive_channel, make_user_auth_headers
diff --git a/engine/apps/public_api/tests/test_routes.py b/engine/apps/public_api/tests/test_routes.py
index a03a238b..126408bc 100644
--- a/engine/apps/public_api/tests/test_routes.py
+++ b/engine/apps/public_api/tests/test_routes.py
@@ -282,6 +282,52 @@ def test_delete_route(
         new_channel_filter.refresh_from_db()
 
 
+@pytest.mark.django_db
+def test_create_route_slack_error(
+    route_public_api_setup,
+):
+    _, _, token, alert_receive_channel, escalation_chain, _ = route_public_api_setup
+
+    client = APIClient()
+
+    url = reverse("api-public:routes-list")
+    data_for_create = {
+        "integration_id": alert_receive_channel.public_primary_key,
+        "routing_regex": "testreg",
+        "escalation_chain_id": escalation_chain.public_primary_key,
+        "slack": {"channel_id": "TEST_SLACK_ID"},
+    }
+    response = client.post(url, format="json", HTTP_AUTHORIZATION=token, data=data_for_create)
+
+    assert response.status_code == status.HTTP_400_BAD_REQUEST
+    assert response.data["detail"] == "Slack isn't connected to this workspace"
+
+
+@pytest.mark.django_db
+def test_update_route_slack_error(
+    route_public_api_setup,
+    make_channel_filter,
+):
+    _, _, token, alert_receive_channel, escalation_chain, _ = route_public_api_setup
+    new_channel_filter = make_channel_filter(
+        alert_receive_channel,
+        is_default=False,
+        filtering_term="testreg",
+    )
+
+    client = APIClient()
+
+    url = reverse("api-public:routes-detail", kwargs={"pk": new_channel_filter.public_primary_key})
+    data_to_update = {
+        "slack": {"channel_id": "TEST_SLACK_ID"},
+    }
+
+    response = client.put(url, format="json", HTTP_AUTHORIZATION=token, data=data_to_update)
+
+    assert response.status_code == status.HTTP_400_BAD_REQUEST
+    assert response.data["detail"] == "Slack isn't connected to this workspace"
+
+
 @pytest.mark.django_db
 def test_create_route_with_messaging_backend(
     route_public_api_setup,
diff --git a/engine/apps/public_api/tests/test_schedules.py b/engine/apps/public_api/tests/test_schedules.py
index 956f59c2..6d041bf9 100644
--- a/engine/apps/public_api/tests/test_schedules.py
+++ b/engine/apps/public_api/tests/test_schedules.py
@@ -844,6 +844,65 @@ def test_create_schedule_invalid_timezone(make_organization_and_user_with_token,
     assert response.json() == {"time_zone": ["Invalid timezone"]}
 
 
+@pytest.mark.django_db
+def test_create_calendar_schedule_slack_error(make_organization_and_user_with_token):
+    organization, user, token = make_organization_and_user_with_token()
+    client = APIClient()
+
+    url = reverse("api-public:schedules-list")
+    # with slack channel id
+    data = {
+        "team_id": None,
+        "name": "schedule test name",
+        "time_zone": "Europe/Moscow",
+        "type": "calendar",
+        "slack": {
+            "channel_id": "TEST_SLACK_ID",
+        },
+    }
+
+    response = client.post(url, data=data, format="json", HTTP_AUTHORIZATION=f"{token}")
+    assert response.status_code == status.HTTP_400_BAD_REQUEST
+    assert response.data["detail"] == "Slack isn't connected to this workspace"
+    # with slack user group id
+    data = {
+        "team_id": None,
+        "name": "schedule test name",
+        "time_zone": "Europe/Moscow",
+        "type": "calendar",
+        "slack": {
+            "user_group_id": "TEST_SLACK_ID",
+        },
+    }
+
+    response = client.post(url, data=data, format="json", HTTP_AUTHORIZATION=f"{token}")
+    assert response.status_code == status.HTTP_400_BAD_REQUEST
+    assert response.data["detail"] == "Slack isn't connected to this workspace"
+
+
+@pytest.mark.django_db
+def test_update_calendar_schedule_slack_error(
+    make_organization_and_user_with_token,
+    make_schedule,
+):
+    organization, user, token = make_organization_and_user_with_token()
+    client = APIClient()
+    schedule = make_schedule(organization, schedule_class=OnCallScheduleCalendar)
+    url = reverse("api-public:schedules-detail", kwargs={"pk": schedule.public_primary_key})
+
+    data = {"slack": {"channel_id": "TEST_SLACK_ID"}}
+
+    response = client.put(url, data=data, format="json", HTTP_AUTHORIZATION=f"{token}")
+    assert response.status_code == status.HTTP_400_BAD_REQUEST
+    assert response.data["detail"] == "Slack isn't connected to this workspace"
+
+    data = {"slack": {"user_group_id": "TEST_SLACK_ID"}}
+
+    response = client.put(url, data=data, format="json", HTTP_AUTHORIZATION=f"{token}")
+    assert response.status_code == status.HTTP_400_BAD_REQUEST
+    assert response.data["detail"] == "Slack isn't connected to this workspace"
+
+
 @pytest.mark.django_db
 def test_create_ical_schedule_without_ical_url(make_organization_and_user_with_token):
     _, _, token = make_organization_and_user_with_token()