This paper describes a successful adaptation of particle swarm optimization (PSO) algorithm to solve the economic dispatch (ED) problem with valve point effects in power system.. In this paper, PSO method is used to describe the equality and inequality constraints in the Economic Dispatch problems. The proposed algorithm has been tested on 3 unit system with quadratic cost functions. Numerical example are solved on Matlab 7 platform using PSO method. Numerical results shows that the proposed PSO based ED algorithm can provide comparable dispatch solutions with reduced cost.