This paper presents a cascade control approach to the design of governors for speed control of hydro turbines in power generation units. The key issues include the problems of model uncertainty, inner and outer loop disturbances, load rejections and attenuation of measurement noise. Gate position deviation signal is used as a supplementary inner loop manipulated variable in the proposed cascade control. The effect of water hammer, travelling waves and inelastic water penstocks is included in the hydro turbine model. The polynomial H. design method is used to design cascade governor controllers. Dynamic weighting functions of the H. design method provide the required control actions. A cascade robust governor ensures that the overall system remains asymptotically stable for all permissible norm-bounded uncertainties and system oscillations. The results presented in the time and frequency domains are compared with conventional PID and PID cascade designs. The results show that the performance of the system is significantly improved by the proposed cascade governor design. Copyright (C) 2004 John Wiley Sons, Ltd.