The integration of distributed generators (DGs) considering renewable energy provides great benefits to the distribution networks, such as, reductions in power loss and improvements of voltage profile. However, such benefits to the distribution networks are constrained with the installation of DGs with proper sizes and locations. In this paper, the optimization for sizing and placement of distributed renewable generators (DRGs) in the electrical distribution networks is presented. The optimum sizes and locations for the DRGs are determined to reduce the power loss in the distribution networks. The genetic algorithm (GA) has been used to solve the optimization problem using MATLAB. For the validation, results of this study are compared with other well-known heuristic optimization techniques and analytical approaches. The numerical studies on the IEEE 33 bus distribution network have revealed that the proposed algorithm is capable for finding the optimum size and place of DRG in the distribution networks. The optimization results using GA are seen very competitive with the result by other well-known heuristic optimization techniques and analytical approaches that have been used for the similar studies. The results from this study signify the use of GA in the research related to planning of renewable energy and power system. © 2018 Institution of Engineering and Technology. All rights reserved.