Cabrera entered the playoff with Kenny Perry and Chad Campbell, who dropped out with a bogey on the first extra hole.
The Argentine then won with a two-putt par after Perry missed a 20-foot par attempt.
The three golfers had tied at 12-under-par 276 in regulation. Campbell shot a 69 in the final round, and Cabrera and Perry both had 71.
Cabrera took his other major title in 2007, capturing the U.S. Open.
Perry, 48, was trying to become the oldest player ever to win a major and seemed in command until he bogeyed the final two holes, creating the playoff.
Cabrera hit a tree on his second shot of the first playoff hole but his ball richocheted onto the fairway and he survived with a par.
Shingo Katayama (68) placed fourth at 278 and Phil Mickelson (67) was fifth at 279. Tiger Woods (68) and three other players shared sixth place.
Copyright 2009 by United Press International.