The installation of DG in the distribution system is challenging for the technical, economic and environmental aspects. The smaller scale generation technologies are developed for minimum cost and today's competition. The range capacities from a few kilowatts to 100MW. The optimal siting and sizing of DG in the distribution system improve the reduces the losses, improves the voltage and improve the economics of the system. However, to find the optimal solution for multi-objective problems, the different optimization methods are studied. This paper study the impact of DG onthe distribution system, Distributed generation, a different approach for optimal siting and sizing impact on utilities and the customers. © 2018 Elsevier B.V., All rights reserved.