This paper proposes a one rank cuckoo search algorithm (ORCSA) for finding the optimal location and sizes of multiple distributed generation (DG) units in distribution networks. The ORCSA is the enhanced version of the cuckoo search algorithm (CSA) to improve convergence speed and provide better optimal solution. In this paper, the optimization problem of DG placement is formulated with multi-objectives of minimum power loss, minimum voltage deviation, and voltage stability improvement. In addition, the power factor of DG units is considered with multiple options by proposing power factor constraints. The proposed method is tested on 69-bus IEEE standard radial distribution system and the obtained results are compared to those from other artificial intelligence methods. The results comparison has indicated that the proposed ORCSA offers better solution than other techniques. Moreover, the results have introduced the operation of DG units at multiple options of power factor instead of only unity power factor under the current standard IEEE 1547. © 2017 IEEE.