The former Countdown brainbox, known for her ability with figures, is the first person to take the Rear of the Year title twice.
The male winner of the prize is singer and television host Olly Murs, who showed he has the X Factor when it comes to a shapely bum.
The duo were chosen in a public poll for the annual award, with organisers saying they received more than 10,000 votes.
Vorderman, 53, said: “I am both surprised and flattered to win the award for a second time - particularly at this stage of my life.
“As I said when I won it in 2011, I always suspected there were a lot of people out there who were glad to see the back of me. It now appears there were even more than I thought.”
The presenter, who stepped down from ITV’s Loose Women earlier this month, intends to make a solo flight around the world after qualifying as a pilot.
Runner-up for the women’s title was chart star and returning X Factor judge Cheryl Cole - who married French restaurateur Jean-Bernard Fernandez-Versini a fortnight ago - while tennis player Andy Murray came second for the men’s award.