Renal histopathology in 87 patients, aged over 60, with nephrotic syndrome were studied. In 57 patients diagnosed as primary glomerular disease, membranous glomerulonephritis (MGN) was of the most common histologic type (52.6% of the cases), and mesangial proliferative glomerulonephritis (21.1%), membranoproliferative glomerulonephritis (12.3%) and minimal change (12.3%) were the other types of primary glomerular disease. In the remaining 30 patients, nephrotic syndrome resulted from secondary glomerular diseases including diabetic nephropathy and renal amyloidosis. In comparison with the nephrotic syndrome of younger age group (669 cases, younger than 60 years of age), the incidence of MGN, diabetes and amyloidosis were significantly higher in the elderly. In contrast with unfavorable prognosis of diabetic nephropathy and amyloidosis, most cases of MGN and minimal change recovered from the nephrotic state with steroid treatment even in the elderly. Thus, a statistical finding that the prognosis of senile nephrotic syndrome is unfavorable as a whole, appears to be ascribable to the increased incidence of secondary glomerular diseases rather than to "aging" itself. The present results that the incidence of diabetic nephropathy was high and the outcome of MGN was favorable in the elderly, taken together with the results from other studies in Japan, are fairly different from the results of similar studies in the Western world.