The glomerular tip nephropathy is a cause of the nephrotic syndrome and has distinct pathological features. Glomerular tufts appear normal on light microscopy except for a segmental lesion invariably present in all glomeruli at the origin of the proximal tubule. Data on twenty adults whose renal biopsies demonstrated this lesion and who were followed for a mean of 7.4 years are analyzed. Eighteen patients were treated with steroids; ten of these had complete remission of proteinuria and seven a significant reduction of their proteinuria. Ten patients had moderately impaired renal function (serum creatinine greater than 120 mumol/l) at presentation, eight received steroids and achieved a reduction in serum creatinine. The prognosis was good, with no patient developing chronic renal failure requiring dialysis.