Indianapolis Motor Speedway announced his death in a press release Monday.
Unser is one of 10 drivers to have won the prestigious Indy 500 at least three times and was the first driver to win the race in three different decades, a feat later matched by Rick Mears.
Bobby was part of the legendary Unser racing car family. His older brother, Jerry Unser, died at Indianapolis Motor Speedway in an accident while training before the 1959 Indy 500. His younger brother, Al Unser, is a four-time Indy 500 winner, and his nephew Al Unser, Jr, has won the race twice. In total, six members of the Unser family raced in the Indianapolis 500.
Unser has been inducted into several motorsport Halls of Fame, including the Indianapolis Motor Speedway Hall of Fame, the International Motorsports Hall of Fame, and the Motorsports Hall of Fame of America.
Bobby Unser is survived by his wife Lisa, sons Bobby Jr. and Robby, and daughters Cindy and Jeri.