Abstract: This study deals with the design and evaluation of a robust controller for generator excitation system to improve the steady state and transient stability. The design is based on fuzzy state feedback controller, applying for the single machine systems and extended to multi-machine systems. The effectiveness of the proposed PSS is demonstrated under different operating regimes. A comparative study of the proposed PSS (FSFPSS: Fuzzy state feedback power system stabiliser) with a conventional PSS such as optimal controllers has been performed and the superiority of the FSFPSS in improving the transient stability of the power generator is demonstrated in a simulation environment.