Overview

Error 18374 appears when Amazon’s catalog system flags two ASINs that appear to describe the same item. The alert shows up in Seller Central as a listing warning, prompting sellers to verify whether the two listings are duplicates or distinct products. Resolving the issue quickly is crucial because duplicate ASINs can suppress visibility, split inventory, and hurt sales performance.

Key Points

• Automatic duplicate detection — Amazon scans new and existing listings for matching attributes such as title phrasing, brand, UPC/EAN, or product dimensions, and raises Error 18374 when similarities cross a threshold.
• Seller verification required — Once the alert is triggered, the seller must examine the two ASINs and tell Amazon if they represent the same SKU or two separate items.
• Risk of multiple SKUs — The error often surfaces when a seller creates a new SKU for an item that already exists in the catalog, or when variations are entered as independent ASINs instead of child items under a single parent.
• Evidence may be requested — If the listings are truly different (e.g., different colors or sizes), Amazon may ask for photos, spec sheets, or other documentation that proves the distinction.
• Impact on listing health — Until the duplicate issue is cleared, the affected pages can be suppressed or receive lower search placement, directly affecting conversion rates.

How to Resolve Error 18374

1. Side‑by‑side attribute comparison — Open both ASIN detail pages in separate tabs and list every data point: title, brand, manufacturer part number, barcode, dimensions, weight, and any unique specifications. For example, compare a “Stainless Steel Travel Mug, 16 oz, Silver” listing with a “Stainless Steel Travel Mug, 16 oz, Black” listing to spot any differences.
2. Determine duplication status
   • Same product — If every attribute matches and only the SKU differs (e.g., two internal SKUs for the same 16 oz silver mug), the listings are duplicates.