In a retrospective study of 82 adults with idiopathic membranous nephropathy, we have studied the predictive factors of renal death. Thirty one patients developed renal failure, sixteen of them progressed to end-stage renal failure (ESRF) (13 males and 3 females). Nine patients developed ESRF in the first 5 years following the renal biopsy. The males and the patients with a nephrotic syndrome have a high risk of ESRF. The age is not a predictive factor of poor outcome. Hypertension seems to be more frequent in patients who developed early but slowly progressive renal failure. Extensive renal interstitial lesions are indicative of poor renal prognosis.