Fifteen children, aged between 2 and 9 years old, with hypospadias (4 penile; 6 penoscrotal; 3 scrotal; 1 perineal) were administered testosterone ointment before one-stage urethroplasty. Temporary penile growth and skin enlargement were obtained in all. Side effects were negligible. The plasma testosterone level was measured before, during and after testosterone administration. During testosterone stimulation, the plasma testosterone level ranged from 30 to 190 ng/dl, and returned to the normal range a week after administration had been stopped. Primary success of hypospadias repair was obtained in 10 of 15 children (66.7%).