Massive proteinuria and pronounced œdema in the congenital nephrotic syndrome are always resistant to corticosteroid and immunosuppressive therapy. Children with this disease invariably die in early childhood. Kidneys were transplanted to three children with congenital nephotic syndrome (including one of Finnish ancestry) and mild to severe uræmia at 21/2, 21/2, and 41/2 years of age. These three children are now well with normal serum-creatinine levels at 4, 7, and 14 months after renal transplantation and have not had recurrence of nephrosis or significant proteinuria. In contrast, recurrence of the steroid-resistant idiopathic nephrotic syndrome is often seen shortly after transplantation. These observations suggest that the basic defect leading to proteinuria in the congenital nephrotic syndrome resides in the kidney and that renal transplantation may successfully cure this disease.