Distributed generation (DG) devices can be strategically placed in power systems to reinforce the network, minimize actual power losses, improve bus voltages and distribution system efficiency. The optimal DG placement method (OPDG) is used to provide the best DG locations and sizes to optimize the operation of the electrical distribution network taking into account DG capacity and voltage limitations. The objective function is formulated to determine the optimal location and size of the distributed generation units (DG) in the distribution network for the reduction of the active power loss and the increase of the voltage profile. Type-I DG is used to solve the problem. The maximum penetration level of DG is considered in a range of 0-50% of the total load. The proposed solution methodology has been implemented and tested in the IEEE 33 and 69 standard bus systems. The test results are also compared with the latest optimization techniques and found that the proposed algorithm is more effective.