Rival owners Rick Penske and Chip Ganassi shared a hug after an Indy 500 duel for the ages.
Four cars separated from the rest of the field in the closing laps, the two Penske cars of Juan Pablo Montoya and Will Power and the two Ganassi cars of Charlie Kimball and Scott Dixon.
Montoya, Power and Dixon took turns swapping the lead several times after a restart with 15 laps to go, but it was ultimately the Penske cars that won the day.
Juan Pablo Montoya, of Colombia, celebrates after winning the 99th running of the Indianapolis 500. Picture/AP
Montoya was chased across the line by his teammate to give Penske his 16th victory in the Indianapolis 500.
Kimball wound up third, followed by his teammate Dixon.
“Great day for Team Penske,” the team owner said.Graham Rahal finished fifth, a solid run for the team part-owned by David Letterman.
Marco Andretti was sixth, followed by Helio Castroneves, JR Hildebrand, Josef Newgarden and Simon Pagenaud, who was strong all day before a wing problem shuffled him back late.
Earlier Dixon had held the lead at the Indianapolis 500 after 163 of the 200 laps.
Dixon passed Simon Pagenaud to move into top spot after a yellow flag incident that saw two pit crew members taken out by James Davison's car.
Dixon is battling Pagenaud and Juan Pablo Montoya for top spot with Pagenaud briefly passing the New Zealander to hold the lead for a lap.
Dixon was looking to win the famous race for a second time after his maiden win in 2008.
Earlier Ed Carpenter, the hometown boy and stepson of IndyCar Series founder Tony George, crashed out of the race when he attempted to pass Oriol Servia entering Turn 1 just past the midway point. Servia came down and clipped Carpenter's nose, sending both of their cars into the wall - and out of the showcase race.
One week ago, Carpenter lost the rear end of his car and backed into the wall in a violent wreck. His car spun around, went airborne and landed upside down before skidding to a stop.
Not long after there was another incident on pit road.
Davison was leaving his stall when he clipped Pippa Mann, who was coming down pit road. Davison's car spun into the stall in front of Tristan Vautier, hitting one of his crew members.
An ambulance came onto pit road and the crew member was loaded into the back. There was no immediate word on the nature or severity of the injuries.
All three of the cars are from Dale Coyne Racing
"Unfortunately I got sent out there at the same time Pippa was coming and we made contact and it sent us into our second team car," Davison said. "Just a very unfortunate situation."
- With AP