Chester police and firefighters were dispatched to a report of a brush fire at about 10:45 p.m. Monday.
When they arrived at an area behind the 200 block of West Elkinton Avenue, they found a partially clothed man on fire.
They quickly put out the flames and found the man was still alive, but had trouble breathing.
Rescuers administered first aid, but the man died at the scene.
Police are not releasing the victim's name until his family has been notified.
Chester police and Delaware County detectives are searching for suspects.
If you have any information on the case, police ask that you call them at 610-447-7908 or 610-891-4700.