Fire crews were called to a fire in a flat at Hoghton, near Preston in the early hours of Saturday morning
Two fire engines from Preston and one from Bamber Bridge attended the incident in Cripple Gate Lane shortly after 3.30am and there were initial fears that someone was trapped inside the building.
But a brigade spokesman said no-one was in fact there and there were no casualties.
The crews, equipped with breathing apparatus, used two hose reel jets to extinguish the fire and portable fan units to extract the smoke and heat.
The cause of the fire is to be established.