Four fire engines and around 25 firefighters were called to a blaze in a shop with flats above in Newington Green, Islington.
A shop was destroyed and part of a flat above was damaged by the fire. There were no reports of any injuries.
The Brigade was called at 0207 and the fire was under control by 0415.
Fire crews from Islington, Stoke Newington and Hackney fire stations attended the incident.
The fire is believed to have been caused by a deep fat fryer.