Abstract: A sofa bed convertible from a sofa to a bed having a self-supporting stationary section, a first movable section slidably attached to the stationary section, and a second movable section slidably attached to the first movable section. Independently supported spaced arms are removably attached to the sides of the stationary section to serve as arm supports for persons seated on the sofa bed, but not as structural supports for the stationary section. A hollow furniture-type back is removably connected between the arms. A hinged mattress overlies the stationary and movable sections when the sofa bed is being utilized as a bed. The rearmost portion of the mattress may be doubled over so that the resulting double-thickness section may slide rearwardly and upwardly into the hollow back for storage, with the forward part of the mattress forming a resilient seating surface when the sofa bed is being utilized as a sofa.