This paper presents an optimal location and sizing of distributed generation with active power injection in radial distribution systems, obtaining an optimum power flow through the particle swarm optimization algorithm (PSO). The proposed purposes are to minimize losses and improve the profile of voltages, fulfilling an objective function of minimizing costs. The restrictions used are balance of powers, voltage margins and power injection limits of the distributed generation. The analysis was carried out in the IEEE 15 nodes and IEEE 33 nodes radial distribution systems, and the implementation was developed in MATLAB mathematical software. The methodology used also allowed to improve the indexes of quality conditions such as the average voltage deviation and the maximum voltage deviation. The results obtained show that the method used makes a location and dimensioning of distributed generation able to …