Firefighters battled the flames for nearly two hours at the flat in Willoughby Park Road, Tottenham at 5.30pm on Sunday.
Another man who was rescued from the property is still in hospital.
A spokesman said: “Part of the flat, on the ground and first floor, was damaged by fire.
“Firefighters wearing breathing apparatus rescued a man from the first floor.
“He was sadly pronounced dead at the scene. Another man was taken to hospital by London Ambulance Service crews.”
London Fire Brigade sent three engines and around 20 firefighters to quell the blaze.
The force had it under control by 7.20pm.
Police said the cause of the fire is under investigation.
Last week a woman was killed when a fire broke out at a nearby residential home called Summerhill Village.
A neighbour said: “I saw some smoke and heard some shouting, then the fire brigade were here and police.
“There were emergency services parked all up the road.
“We have heard one of our neighbours has died we are all devastated.”
Another said: “We heard the fire engines and have seen the forensic officers here. It’s flats where elderly people live that it happened. Some are quite vulnerable. It’s a tragedy.”