Firefighters responded to reports of a blaze inside a single-story duplex located at 3918 Midvale Ave. at about 7 p.m., according to a witness and Battalion Chief Lisa Baker.
Arriving crews found the kitchen on fire and discovered a man who wasn't breathing and didn't have a pulse, Baker said.
The man was taken to a Highland Hospital, where he was pronounced dead, Baker said.
Wilfried Eisinger, who lives across the street from the home that caught fire, said the fire happened quickly.
"The flames were huge within 10 minutes," he said. "I smelled smoke, and I was thinking my wife was cooking food. There was smoke all over the neighbor's house."
Eisinger said he saw a man with burn wounds on his face taken away in an ambulance. He wasn't sure if he knew the victim.
The blaze was contained to the kitchen, and no other injuries were reported.
The fire was contained within about 30 minutes, according to Officer Holly Joshi with the Oakland Police Department, which assisted the fire department.
Baker said the house sustained about $15,000 in damage to the structure, and about $5,000 worth of belongings were destroyed.
The cause of the fire remained under investigation, but Joshi said preliminary results have ruled out arson.
The coroner's bureau had not identified the victim Friday afternoon.