diff --git a/InvenTree/order/api.py b/InvenTree/order/api.py
index 634a07c580..25b974c94e 100644
--- a/InvenTree/order/api.py
+++ b/InvenTree/order/api.py
@@ -495,7 +495,7 @@ class PurchaseOrderLineItemList(APIDownloadMixin, ListCreateAPI):
     search_fields = [
         'part__part__name',
         'part__part__description',
-        'part__MPN',
+        'part__manufacturer_part__MPN',
         'part__SKU',
         'reference',
     ]