diff --git a/services/procurement/app/api/internal_demo.py b/services/procurement/app/api/internal_demo.py
index d98b10c5..54547294 100644
--- a/services/procurement/app/api/internal_demo.py
+++ b/services/procurement/app/api/internal_demo.py
@@ -390,12 +390,16 @@ async def clone_demo_data(
                 )
                 raw_status = 'draft'
             
+            # Transform supplier_id to match transformed supplier IDs in suppliers service
+            raw_supplier_id = po_data.get('supplier_id')
+            transformed_supplier_id = transform_id(raw_supplier_id, virtual_uuid) if raw_supplier_id else None
+
             # Create new PurchaseOrder
             new_order = PurchaseOrder(
                 id=str(transformed_id),
                 tenant_id=virtual_uuid,
                 po_number=f"{session_id[:8]}-{po_data.get('po_number', f'PO-{uuid.uuid4().hex[:8].upper()}')}",
-                supplier_id=po_data.get('supplier_id'),
+                supplier_id=str(transformed_supplier_id) if transformed_supplier_id else None,
                 order_date=adjusted_order_date,
                 required_delivery_date=adjusted_required_delivery,
                 estimated_delivery_date=adjusted_estimated_delivery,