A boy developed a nephrotic syndrome at the age of two years, and remained steroid sensitive for twelve years. In this time more than twenty relapses occurred. Two renal biopsies showed minimal changes. Renal function was normal all along. At an age of 14 years he developed an irreversible renal failure. Since this time he remained dependent to dialysis. A third renal biopsy now shows a perimembranous glomerulonephritis with a diffuse interstitial fibrosis.