The existence of an HIV-related nephropathy as a distinct disease entity is controversial. We observed a high incidence of renal disease in our AIDS patients. Of 182 patients, 59 patients (32.4%) were found to have heavy proteinuria (greater than 2 g/24 h). Of these, 24 patients had slow progression of renal insufficiency and 2 patients had rapid deterioration to end stage renal disease. There was a notable absence of hypertension in these cases. The incidence of proteinuria was similar in blacks and hispanics; however 22.8% of blacks had renal insufficiency as compared to 6.9% of hispanics. There was no difference in the incidence of heavy proteinuria between intravenous drug abusers (32.3%) and nonabusers (33.3%). Renal morphology when examined showed characteristic changes, including cytomembranous structures and virus-like particles. These changes were similar in patients with heavy or light proteinuria, though they were less severe in the latter. We conclude that a HIV-related nephropathy exist and the presence of cytomembranous structures and virus-like particles in the renal tissue raises the possibility of a viral etiology for this disorder.