An adaptive fuzzy sliding-mode control system, which combines the merits of sliding-mode control, the fuzzy inference mechanism and the adaptive algorithm, is proposed. First a sliding-mode controller with an integral-operation switching surface is designed. Then a fuzzy sliding-mode controller is investigated in which a simple fuzzy inference mechanism is used to estimate the upper bound of uncertainties. The fuzzy inference mechanism with centre adaptation of membership functions is investigated to estimate the optimal bound of uncertainties. Position control of a permanent magnet synchronous servo motor drive using the proposed control strategies is illustrated.