Initial autopsy studies concerned primarily with the systemic manifestations of the acquired immunodeficiency syndrome (AIDS) did not indicate that significant renal problems were likely to occur in AIDS patients. However, several recent studies have suggested that important renal and electrolyte disorders develop frequently in at least some groups of AIDS patients. In this report, we review current information concerning such disorders and describe our study of the frequency and types of renal lesions in the first 50 AIDS patients undergoing autopsy at this institution. We conclude that a number of renal lesions and electrolyte abnormalities occur in AIDS patients, although the frequency and nature of these problems vary considerably from center to center. Studies from several centers, including our own, indicate that AIDS patients are particularly likely to develop tubulointerstitial lesions (such as nephrocalcinosis and interstitial nephritis) and electrolyte disorders. Additional studies from specific centers in New York City, Miami, Detroit, and Los Angeles indicate that AIDS patients can also develop glomerular lesions, including a variant of focal and segmental glomerulosclerosis (FSGS) associated with heavy proteinuria and rapidly progressive renal failure. Although FSGS is not commonly observed in all centers, AIDS patients with this lesion appear to have a distinctive combination of clinical and pathological features, suggesting that they have a specific "human immunodeficiency virus (HIV)-associated" nephropathy. Preliminary evidence suggests that this lesion may be related to direct renal HIV infection, although confirmation of this possibility is needed. The approach to the AIDS patient with renal disease should involve correction of reversible disorders and consideration of dialysis as necessary.