Abstract: A portable bed assembly for use on a pick up truck, camper, station wagon or other recreational vehicle includes an elongate framework having a width designed to fit between rear wheel wells on a motor vehicle, and a length which fits snugly within the vehicle when the rear thereof is closed. The portable bed is mounted on rollers which ride on rails mounted on the original deck or bed of the motor vehicle. The framework includes a pair of foldable leg assemblies with one mounted on each end of the portable bed assembly. A locking mechanism maintains the portable bed assembly in mounted position along the rails on the original motor vehicle bed or rear deck. When the locking mechanism is released and the rear of the motor vehicle is opened, or the tailgate is positioned horizontally, the portable bed assembly will roll outwardly of the back of the motor vehicle.