A wheelchair including a wheeled base assembly provided with an upright assembly thereon, the latter including a pair of vertical post arrangements which are provided adjacent front corners of the wheelchair and are vertically extendible and retractable. The upright assembly includes a pair of generally parallel and approximately horizontal arms which are mounted adjacent upper ends of the upright post arrangements. A seat assembly is removably attached to and positioned between the arms. The seat assembly includes a seat portion defined by normally vertically superimposed upper and lower seat subassemblies. The upper subassembly has an enlarged opening formed centrally therethrough. The lower subassembly can be detached and moved from beneath the upper subassembly to permit the seat portion of the wheelchair to be positioned directly over and utilized in conjunction with a conventional toilet so as to not require removal of the occupant from the seat assembly.