Partial replacement of Ru in chalcogenide nanoparticles (RuxSey) by a less noble metal, such as Fe, was studied by electrochemical and materials-characterization techniques. The synthesis of the nanoparticles consisting of Ru, Fe, and Se was performed using two different chemical routes, which led either to a combination of RuxSey with oxidized iron or a true alloying of iron with the RuxSey bulk. The physical-chemical properties of the different types of three-component system were subsequently examined. The electrochemical performance in oxygen reduction reaction (ORR) in acidic medium (0.5 M H2SO4) was evaluated relative to the iron-free catalyst. The results demonstrate that the reaction mechanism (four-electron charge transfer) is not perturbed at the modified metal center, even when Ru is replaced by 50 at.% of Fe.