Six fire engines and around 40 firefighters were called to a fire at a disused church and community centre on Woodgrange Road in Forest Gate.
Part of the ground floor of the building was damaged by fire. One man was taken to hospital by London Ambulance Service crews.
Station Commander Jim Ryan, who was at the scene, said: “Crews arrived to find a fire at a building which was previously used as a church and community hall.
“One man had left the building before the Brigade arrived and firefighters carried out a search of the property as a precaution.
“Woodgrange Road was closed between Osborne Road and Romford Road whilst crews worked to make the scene safe.”
The Brigade was called at 10.58pm and the fire was under control by 11.55pm. Fire crews from Stratford, Leytonstone, East Ham, Leyton and Ilford fire stations attended the scene.
The cause of the fire is under investigation.