Abstract: A foldable step stool comprises a pair of rectangular frame members, one disposed within the other and having pivotally connected side rails thus permitting the members to assume an open position, in which the side rails intersect in an "X"-configuration, and a closed position in which the inner frame is contained entirely within the outer frame. Two steps extend between the side rails of the frame members, the ends of one step being pivotally secured to the side rails of the inner frame member and having a pin-and-slot connections to the side rails of the outer frame member. The second step is similarly arranged with the pivotal and pin-and-slot connections reversed with respect to the inner and outer frame members. When in the closed position, the steps lie completely within the three dimensions of the outer frame member.