Power system stabilizers (PSS) are added to excitation systems to enhance the damping during low frequency oscillations. In this paper, the design of PSS for single machine connected to an infinite bus using fast output sampling feedback is proposed. The non-linear model of a machine is linearized at different operating points and 16 linear plant models are obtained. For all of these plants a single stabilizing state feedback gain, F is obtained. A robust fast output sampling feedback gain which realizes this state feedback gain is obtained using linear matrix inequalities approach. This method does not require state of the system for feedback and is easily implementable. This robust fast output sampling control is applied to non-linear plant model of one machine at different operating (equilibrium) points. This method gives very good results for the design of PSS. © 2003 Elsevier Science B.V. All rights reserved.