Due to the usage of high voltage direct current (HVDC) transmission links extensively in recent years, it requires more studies in this issue. Two-terminal HVDC transmission link is one of most important elements in electrical power systems. Generally, the representation of HVDC link is simplified for optimal reactive power flow (ORPF) studies in power systems. ORPF problem of purely AC power systems is defined as minimization of power loss under equality and inequality constraints. Hence, ORPF problem of integrated AC-DC power systems is extended to incorporate HVDC links taking into consideration power transfer control characteristics. In this paper, this problem is solved by genetic algorithm (GA) that is an evolutionary-based heuristic algorithm for the first time. The proposed method is tested on the modified IEEE 14-bus test system, the modified IEEE 30-bus test system, and the modified New England 39-bus test system. The validity, the efficiency, and effectiveness of the proposed method are shown by comparing the obtained results with that reported in literature. Thus, the impact of DC transmission links on the whole power systems is shown. (C) 2013 Elsevier Ltd. All rights reserved.