Four fire engines and around 25 firefighters attended a fire at a dry cleaners on Essex Road in Islington.
Part of the ground floor of the shop was damaged by the fire.
A fire fighter had to be treated by paramedics and transported from the fire ground by ambulance to hospitial
The fire was discovered by a passing bus driver who noticed the smoke emitting from the roller shutter that secured the shop and called the Brigade.
The Brigade was called at 1.49am and the fire was under control by 3.12am.
Fire crews from Islington, Shoreditch, Stoke Newington and Holloway fire stations were at the scene.
The cause of the fire is under investigation.
The condition of the firefighter or his injuries are not known at this time