When did the USPTO start using WIPO Standard ST.16 codes?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

The United States Patent and Trademark Office (USPTO) began implementing WIPO Standard ST.16 codes on January 2, 2001. As stated in MPEP 901.04(a):

On January 2, 2001, the United States Patent and Trademark Office (USPTO) began printing the World Intellectual Property Organization (WIPO) Standard ST.16 code on each of its published patent documents.

This change was part of a broader effort to standardize patent document identification across different patent offices worldwide, making it easier for patent professionals and researchers to interpret and classify patent documents from various countries.