In this paper, the problem of disturbance attenuation with internal stability for nonlinear systems with Markovian jumping parameters is considered. It is shown that this problem is solvable if there exists a set of smooth positive semi-definite functions satisfying certain Hamilton-Jacobi-Isaacs inequalities. Furthermore, it is shown that if this solution exists, it represents a stochastic Lyapunov function for the closed-loop nonlinear system.