The MPN field is intended to inform Google’s index of a product’s Manufacturer Part Number. For years, the MPN played a supporting role to the GTIN attribute in Google Shopping feeds, but that’s about to change. 

Beginning September 2021, Google Merchant Center will enforce the accuracy of MPNs in product feeds.

A little background: The MPN field is required for all products in a merchant’s feed that does not have a manufacturer-assigned GTIN. However, the MPN attribute is optional for custom-made products and products that don’t have a clearly associated part number from the manufacturer, for example, art, custom t-shirts, novelty products, and handmade products. MPNs are a static identifier of a product that is universal to all distributors, wholesalers, resellers. This can usually be found near the UPC number on the box or label.

Source: Google

How MPN accuracy enforcement is changing

In August 2021, Google began issuing item-level warnings for "Incorrect product identifier [mpn]" in the diagnostics page of your Merchant Center account. These warnings are intended to notify merchants that the MPN submitted in their product feeds has an incorrect value.

In September 2021, Google will begin disapproving products whose MPNs were issued warnings for "Incorrect product identifier [mpn]".

What to do if your product feed gets an "Incorrect product identifier [mpn]" warning

There are 2 ways to fix the "Incorrect product identifier [mpn]" disapproval:

  1. Replace the value in the MPN attribute with a valid part number 
  2. Delete the incorrect value in your product feed. If no MPN is available, be sure to use a GTIN in your product feed.

If you’re having a hard time finding your product’s MPN, try looking for it in your product data under these other names:

  • Model number
  • Part number
  • PN
  • P/N
  • part no.
  • part #