diff --git a/backend/src/db/migrations/20251018061215_sub-org.ts b/backend/src/db/migrations/20251018061215_sub-org.ts
index bd577fe75..d048a23d3 100644
--- a/backend/src/db/migrations/20251018061215_sub-org.ts
+++ b/backend/src/db/migrations/20251018061215_sub-org.ts
@@ -14,14 +14,10 @@ export async function up(knex: Knex): Promise<void> {
       t.foreign("rootOrgId").references("id").inTable(TableName.Organization).onDelete("CASCADE");
 
       t.dropUnique(["slug"]);
+      t.unique(["rootOrgId", "parentOrgId", "slug"]);
     });
 
     // had to switch to raw for null not distinct
-    await knex.raw(`
-ALTER TABLE "organization"
-ADD CONSTRAINT "organization_root_parent_slug_unique"
-UNIQUE ("rootOrgId", "parentOrgId", "slug") NULLS NOT DISTINCT;
-`);
   }
 
   const hasIdentityOrgCol = await knex.schema.hasColumn(TableName.Identity, "orgId");
diff --git a/backend/src/services/org/org-service.ts b/backend/src/services/org/org-service.ts
index 6334322eb..265612d55 100644
--- a/backend/src/services/org/org-service.ts
+++ b/backend/src/services/org/org-service.ts
@@ -516,6 +516,12 @@ export const orgServiceFactory = ({
       }
     }
 
+    if (slug) {
+      const existingOrg = await orgDAL.findOne({ slug, rootOrgId: null });
+      if (existingOrg && existingOrg?.id !== orgId)
+        throw new BadRequestError({ message: `Organization with slug ${slug} already exist` });
+    }
+
     if (googleSsoAuthEnforced) {
       if (googleSsoAuthEnforced && currentOrg.authEnforced) {
         throw new BadRequestError({