The second-seeded Nadal has never lost in 21 matches at the French Open. He is the first man to win three straight French Open titles since Bjorn Borg won four straight from 1978-81.
Nadal's victory ended Federer's bid to complete and career Grand Slam and become the first player since Rod Laver in 1969 to hold all four men's major championships at one time.
Federer, still looking for his first French Open title, lost to Nadal in the semifinals in 2005 and in last year's title match. Since then, Federer has won at Wimbledon, the U.S. Open and the Australian Open.
Nadal's victory Sunday gave him his 22nd career title and his fifth of 2007.