This paper presents optimal reconfiguration of radial distribution network with integration of distributed energy resources (DER) using modified particle swarm optimization (PSO) algorithm. The advantages of integration of DER in distribution system are minimizing power losses, improving voltage profiles and load factors, eliminating system upgrades, and reducing environmental impacts. However, the presence of DER could also cause technical problems in voltage quality and system protection. Optimal reconfiguration of distribution network is subjected to minimize power loss and to improve voltage profile in order to enhance the efficiency the distribution system. In this study, reconfiguration method is based on an improved PSO. The method has been tested in a 60-bus Bantul distribution network of Yogyakarta Special Region province, Indonesia. The simulation results show that optimal reconfiguration of the network with integration of DER has successfully enhancing the efficiency of the distribution system.