Abstract: A collapsable frame for children's furniture, of the type which is formed of a rectangular enclosure with four independent side members. The side members are fixed together but detachable from each other and a base. In application to a playpen, the base is made up of two co-planar sections which on their two opposing edges have tongues on each in the continuous plane for support and abutt against their respective lower side beams of the two opposite side members. The lower side beams of the other two side members carry the support of the corresponding edges of the base panels, which edges abutt against the bars of the side members, thus providing rigidity of the entire frame.