Many patients with idiopathic membranous nephropathy are elderly, but little is known about the natural or treated history of these patients. We have studied a cohort of 155 patients with membranous nephropathy who were recruited and followed-up over a 20 year period. We have compared the clinical features and outcome of the older (>60 years) and younger age groups. There was a higher incidence of an identifiable cause for the nephropathy in older patients. At presentation with idiopathic disease, older patients were more often hypertensive and had worse renal impairment than the younger cohort, but had a similar levels of proteinuria, hypoalbuminemia and hematuria. Thrombotic complications and minor rheumatological complaints were more common in the older patients. Prognosis for life and renal survival was worse in the older onset patients. Treatment was well tolerated in selected older patients and was associated with a better outcome in those selected for treatment.