Paragraph 1 of Article 5-02 of the Treaty establishes that the Parties shall prepare a single format for the certificate of origin, which may be modified by prior agreement between them. According to Article 17-01 of the Treaty, the Administrative Commission of the Treaty (Commission) is entitled to, within the scope of its powers, adopt the agreement reached by both countries. Because of this, through Decision No. 3/2019, it is announced the modification of the certificate of origin and its respective filling instructions, for which the Republic of Uruguay notified on September 28, 2020 the conclusion of its internal procedures and, on the other hand, the United Mexican States made its notification on October 19, 2020. As a result, it is necessary to publish this legal instrument to notifiy the content of Decision No. 3/2019 to foreign trade operators.