Nadal, who won the French Open, Wimbledon and the U.S. Open, won the award given by the International Tennis Federation for the second time.
Wozniacki, a Dane who won six tour titles this year to take the No. 1 ranking but failed to reach a Grand Slam final, won for the first time.
Nadal, who completed a career Grand Slam by winning in New York, says "after a difficult year in 2009, it was an amazing feeling to regain the No. 1 ranking and finally win the U.S. Open."
In doubles, Bob and Mike Bryan won the men's award while Gisela Dulko and Flavia Pennetta won the women's.
Nadal set for Mallorca roleWozniacki defeats Dementieva in Pan Pacific final
