It is important that you do not allow your Mexican passport to expire as you will then have to apply for a Mexican passport as a first time applicant. You will have to go into a Mexican consulate with your old passport and required documents in order to renew your Mexican passport. They will assist you in making an appointment with a Mexican consulate nearest you. Your first step in the Mexican passport renewal process is to make contact with the MEXITEL (87) passport helpline. Renewing a Mexican passport in the U.S is relatively simple and straightforward.