Both fighters made weight for Tuesday night's championship bout at Table Mountain, the one they are calling "Final Victory".
44-year-old Christy Martin, who says this will probably be her last fight, tipped the scale at just over 150 pounds. 45-year-old Mia St. John, wearing jeans and a bikini top, weighed-in at 146.
This is the second meeting between the boxers, with the WBC Super Welterweight Title on the line.
Martin won their first bout, nearly a decade ago, in a unanimous decision. Her plan is to win her 50th career fight and then retire.
St. John's last bout was nearly two years ago. Martin has not fought in 14 months.
The first fight on the card is set to go off at 6:30 p.m. at Table Mountain.