In 32 renal transplant patients neutrophil phagocytic activity was evaluated using living bacterial cells of Staphylococcus aureus Oxford 209 P strain. The total group of patients was divided into two subgroups according to the kind of the applied immunosuppressive treatment 1) cyclosporin--12 patients treated with cyclosporin A along with prednisone and 2) azathioprine--20 patients treated with azathioprine along with prednisone. The index of phagocytizing cells i.e. the percentage of neutrophils phagocytizing the bacterial cells was assessed in the investigation of phagocytosis. In the renal transplant patients as compared with the control group, statistically significant increase in the phagocytic of peripheral blood neutrophils in relation to the used bacterial cells of Staphylococcus aureus Oxford 209 P strain was found. Statistically significant differences in the investigated range were also present between the compared subgroups. In the cyclosporin subgroup statistically significant increase was revealed in the percentage of phagocytizing neutrophils.