Abstract: A walker for assisting a physically impaired person in ascending and descending stairs has the four legs pivotally attached to the upper frame of the walker. When the walker is in use, the legs are locked against any pivotal movement; so that the walker provides a stable support for the person using it. When stairs are to be negotiated, a locking member is released to permit relative pivotal movement of the legs with respect to the side portions of the walker frame to be effected. Thus, the front of the frame may be lifted relative to the rear, causing the legs to pivot generally toward the rear by an amount sufficient to permit the front legs to be placed on a step of a staircase. After this has been done, the legs again are locked into position; and the walker maintains this relative position so that the person using it may negotiate the stairs. A reverse of this operation is effected for descending stairs.