What to do before 'I do' September 21, 2002 Share 1 -- MEXICO CITY -- Before clients tie the knot in Mexico, certain requirements must be met. Couples must provide: • A certified copy of each partner's birth certificate or valid passport. • Results of a blood test taken within 15 days of the wedding date. Some destinations require the test be done in Mexico or at least notarized by a Mexican doctor. • A copy of a tourist card or visa. • Four witnesses. Some destinations require Mexican witnesses, while others are fine with U.S. citizens. • A certified copy of a divorce decree, if either of the couple is divorced. Also, a year must elapse from the final dissolution of the previous marriage. • A certified copy of a spouse's death certificate, if either of the partners is widowed.