The min-max robust control synthesis for uncertain nonlinear systems is solved using Takagi-Sugeno fuzzy model and fuzzy state observer. Existence conditions are derived for the output feedback min-max control in the sense of Lyapunov asymptotic stability and formulated in terms of linear matrix inequalities. The convex optimization algorithm is used to obtain the minimum upper bound on performance and the optimum parameters of min-max controller. The closed-loop system is asymptotically stable under the worst case disturbances and uncertainty. Benchmark of inverted pendulum plant is used to demonstrate the robust performance within a much larger equilibrium region of attraction achieved by the proposed design.