diff --git a/frontend/app/inventory/page.tsx b/frontend/app/inventory/page.tsx
index bae11a8e..6e512398 100644
--- a/frontend/app/inventory/page.tsx
+++ b/frontend/app/inventory/page.tsx
@@ -170,6 +170,9 @@ export default function InventoryPage() {
     if (!selectedItem) return;
     try {
       const updated = { ...selectedItem, ...editedItem };
+      if (updated.part_number && updated.part_number.trim().length === 0) {
+        throw new Error("Part number cannot be empty");
+      }
       if (updated.part_number) updated.part_number = updated.part_number.toUpperCase();
 
       await db.items.update(selectedItem.id!, updated);