This paper presents a two stage solution methodology for deterministic unit commitment problem. In the first stage the ON/OFF status of units is determined by priority list method while in the second stage the economic load dispatch has been solved by Particle swarm optimization technique. The proposed technique is applied in MATLAB environment on two different cases comprising of four and ten generating units respectively. It is observed that for both the cases the overall production cost obtained through the proposed technique is better than the results reported thus far. © 2016 IEEE.