Abstract <p> <b>Objectives:</b> The aim of this work was to study the effect of nanocluster polyoxometalate {Mo₇₂Fe₃₀} on macrophages. In vitro studies of polyoxometalate’s effect on cultured macrophages allowed us to evaluate the reaction of immune cells (in particular, peritoneal and alveolar macrophages) to the nanoparticles. <b>Results and discussion:</b> The analysis of the obtained data allowed to establish that {Mo₇₂Fe₃₀} is not toxic for peritoneal and alveolar macrophages, has no significant effect on the morphology of cells, as well as on the activity of α-naphthyl acetate esterase. <b>Conclusion:</b> However, polyoxometalate significantly reduces phagocytic activity, which may indicate possible polarization of macrophages. The obtained results confirm the possibility of using {Mo₇₂Fe₃₀} in the field of biomedicine.</p>