Between November 1985 and November 1989, percutaneous renal biopsy was performed in 32 patients aged 75 or more (mean age 78). The major clinical presentations were nephrotic syndrome in 22 patients, variable amounts of proteinuria in 6 patients and unexplained severe renal insufficiency in 4 patients. In 27 cases the histological study revealed a glomerular disease. Minimal change disease (7 cases), membranous nephropathy (6 cases), amyloidosis (5 cases) and crescentic glomerulonephritis were the most frequent types. The rate of complications after biopsy was low (3 percent) with only one retroperitoneal hematoma. Owing to the atypical renal presentation of some glomerulopathies in the elderly, renal biopsy was useful to differentiate between minimal change disease, membranous nephropathy and amyloidosis. In 4 patients with minimal change disease, remission of nephrotic syndrome was obtained with corticosteroids. Moreover renal biopsy allowed to detect underlying diseases and gave indications to initiate specific therapy particularly in crescentic glomerulonephritis the outcome of which remained unfavourable. It is concluded that, even in elderly, renal biopsy is a valuable and safe diagnostic tool to obtain a rapid diagnosis, particularly in glomerular diseases, leading to a biopsy-guided therapy. It must therefore have the same indications as in younger adults with glomerular syndrome or rapidly progressive renal insufficiency.