Adriamycin induces a nephrotic syndrome in rats characterized by severe ultrastructural changes of visceral epithelial cells similar to those observed in puromycin aminonucleoside (PA) nephrosis and in human 'minimal changes' glomerulopathy. Since steroids have been shown to be effective in human 'minimal changes' glomerulopathy and in PA nephrosis, we undertook the present study to assess whether steroids had a therapeutic effect on adriamycin nephrosis. Groups of rats injected with different doses of adriamycin were subsequently treated with prednisolone. No significant differences were observed in proteinuria and in ultrastructural findings between the control and the steroid-injected animals. This study suggests that the mechanism underlying adriamycin-induced nephrotic syndrome might be different from that responsible for PA nephrosis or human 'minimal changes' glomerulopathy.