Distributed generation (DG)sources are becoming more prominent in distribution systems due to the incremental demands for electrical energy. Locations and capacities of DG sources have profoundly impacted on the system losses in a distribution network. In this paper, a novel crisscross optimization algorithm(CSO)is presented for optimal location and capacities of DG on distribution systems. The objective is to minimize network power losses, achieve better voltage regulation and improve the voltage stability within the frame-work of system operation and security constraints in radial distribution systems. A detailed performance analysis is carried out on IEEE 33 bus systems to demonstrate the effectiveness of the proposed methodology.