The document describes using a particle swarm optimization (PSO) algorithm to solve the unit commitment problem (UCP) in electrical power systems. The UCP involves determining the optimal daily startup and shutdown schedule for power generating units to minimize costs while meeting demand and operational constraints. PSO is a soft computing technique inspired by animal social behavior that is applied to find near-optimal solutions. Test results are presented applying PSO to solve the UCP for 6-unit and 10-unit power system models using load data over a 24-hour period. The results demonstrate the effectiveness of PSO for solving the short-term UCP.