The unidentified man received burns to his neck, face and hands, and is expected to survive, KTLA-TV, Los Angeles, reported Tuesday.
Investigators say they have no motive for the attack, but believe it may have occurred during a robbery attempt.
Neighbors say the man was returning from a convenience store when he was set on fire.
"His shirt was off. He ripped everything off and threw it on the ground. We put a blanket on him, try to calm him down. He was in a lot of pain," witness Bob Efford said.
Police said they have no suspects thus far.