Abstract: A wheelchair lift apparatus which may be adapted for use in an existing motor vehicle in lieu of a seat structure removably coupled to the floor pan. The lift apparatus includes a motor driven horizontal screw for laterally moving a platform across the vehicle to exit the rear passenger compartment through a side door opening. The platform has a vertical side extension and carries a foldable wheelchair, for example, whose two sides collapse inwardly. The lift apparatus further includes motor driven linkage members for pivoting the platform and folded wheelchair from outside the rear passenger compartment toward the front of the vehicle. The platform and folded wheelchair are next vertically adjusted alongside either the driver or a front seat passenger door opening, depending upon whether the side door opening is on the right or left side of the vehicle.