Six fire engines and around 40 firefighters were called to a fire at a disused office building on Nelson Street in East Ham.
Part of the roof of the four-storey building was damaged by the blaze. There were no reports of any injuries.
The Brigade was called at 2242 and the fire was under control by 0108. Fire engines from East Ham, Plaistow, Barking, Stratford and Poplar fire stations were at the scene.
The cause of the fire is under investigation.