Abstract: As a rule, wheel-chairs have large(-diameter) drive wheels (3) and small(-diameter) steerable wheels (5), and wheel-chairs for indoor operation have their drive wheels as their rear wheels, while wheel-chairs for outdoor operation have their drive wheels (3) as front wheels. In the wheel-chair according to the invention, the seat assembly (6) is mounted for rotation about a vertical axis by means of a supporting column (14) above the chassis (1), such that, depending on the purpose of use of the wheel-chair, the large drive wheels are selectively disposed in the front or rear position with respect to the seat(ing) direction. In this way, the wheel-chair may be used both inddors and outdoors in an optimum manner. Additional positioning alernatives of the seat assembly, e.g. at .+-.90.degree. relative to the chassis, open to the user new possibilities of utilization.