The effects of captopril on morphologic changes and clinical course of adriamycin (ADR) nephropathy in spontaneously hypertensive rats (SHR) were examined. After ADR infections rats were divided into two groups: ADR-C group (n = 20) given captopril (60 mg/kg per day) and ADR group (n = 19) receiving no antihypertensive treatment. SHR were examined every 6 weeks. Captopril normalized systemic blood pressure, but failed to prevent proteinuria. It slowed down renal function deterioration in the early stage of ADR nephropathy (weeks 6 and 12), but at the end of the study both groups had the same degree of renal failure irrespectively of whether blood pressure was well controlled with captopril or hypertension persisted. Captopril slowed down mesangial expansion in the early stages of ADR nephropathy, but at the end of the study there was no statistically significant difference between these two groups. Treatment with captopril also reduced the development of glomerular sclerosis.