Abstract: A new scheme of an adaptive fuzzy sliding mode controller for a class of uncertain nonlinear systems is proposed in this paper. The design is based on a modified Lyapunov function and the approximation capability of the second type fuzzy systems. In addition, the approach is able to avoid the requirement of the upper bound of the first time derivative of the control gain, which is assumed to be known a priori in some of the existing adaptive fuzzy/neural network control schemes. By theoretical analysis, the closed-loop fuzzy control system is proven to be globally stable in the sense that all signals involved are bounded, with tracking errors converging to zero.