Power System Stabilizer (PSS) is installed in the Automatic Voltage Regulator (AVR) of the generator, it must be capable of providing appropriate stabilization signals over a broad range of operating conditions and disturbances. Traditional PSS relay on robust linear design methods. In order to eliminate to cover a wide range of operating conditions, expert or rule based controllers have also been proposed. Fuzzy logic as a robust control design method has shown promising results. In this paper, a systematic approach to fuzzy logic control design is proposed.  This paper presents a study of Fuzzy Logic Power System Stabilizer (FLPSS) for stability enhancement of a two-area four-machine system. In order to accomplish the stability enhancement, speed deviation (??) and acceleration power deviation (?p) of the rotor synchronous generator have been taken as the inputs to the fuzzy logic controller. These variables show significant effects on damping the generator shaft mechanical oscillations. The stabilizing signals have been computed using fuzzy membership function depending on these variables. The performance of the system with FLPSS is compared with Conventional Power System Stabilizer (CPSS) and the system with PSS.