This study addresses the issue of photovoltaic (PV) systems optimal allocation in electric distribution network. A case study of using particle swarm optimization (PSO) and genetic algorithms (GA) is presented. The objective function of the problem is to minimize system losses while improving voltage profile. The study considers the network of Masirah Island, Oman, as a case study system. The study includes two stages. In the first stage, the test system is modeled and simulated using the MATLAB load flow toolbox. In the second stage, both PSO and GA optimization tools are used to find the optimal allocation of PV systems. Both algorithms resulted in similar values for both the objective function value and decision variables. Simulation results shows that technical real power losses represent 2.1% of the total load. However, the optimal allocation of PV systems at five buses can reduce losses by 50%.