This paper presents a fuzzy-sliding mode controller (FSMC) for the automated load frequency control in a windhydro-thermal hybrid power system. The wind energy is integrated with hydro and thermal system to minimize the effect of uncertainty in wind speed. The performance of the proposed controller is studied under wind speed load variation. The fuzzy sliding mode controller is compared with a fuzzy-PI controller on the basis of various performance parameters such as peak overshoot and settling time. It has been found to perform better than the fuzzy_PI controller under different operating conditions.