The 52nd International 500 Mile Sweepstakes was held at the Indianapolis Motor Speedway in Speedway, Indiana on Thursday May 30, 1968. For the second year in a row, one of Andy Granatelli's STP Turbine-powered machines was leading late in the race, but once again, it failed within sight of victory.

On lap 174 Lloyd Ruby's engine misfired allowing Joe Leonard to take the lead in the Lotus 56 Turbine. Leonard, however, suffered a flameout on the lap 191 restart, and rolled to a silent and shocking halt. Bobby Unser in the venerable piston-powered Offenhauser, inherited the lead, and despite gear linkage trouble, went on to win his first of three Indy 500 victories.

This was the final Indianapolis 500 to feature a front-engined car in the starting field. Of the 33 cars, 32 were rear-engined machines (including three turbines). Jim Hurtubise's entry, which dropped out after only nine laps, was the last front-engine car to race in the 500. This was also the first 500 won by a turbocharged engine.

During the month, film crews were on hand to film various action shots and of the race proceedings to be used in the upcoming movie Winning, starring Paul Newman.

With 9.25 inches of precipitation in the Indianapolis area, the 1968 race featured the wettest month on record for the Indy 500. Rain hampers practice and qualifying, but does not affect race day.

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