Dysgenetic male pseudohermaphroditism is a disorder of sexual differentiation in which patients present with bilateral dysgenetic testes, persistent müllerian structures, cryptorchidism and inadequate virilization. There were 10 patients with this syndrome seen at our hospital between 1956 and 1976. In this series, there was a 30 per cent incidence of testicular tumors. Because patients with dysgenetic male pseudohermaphroditism have a high incidence of testicular tumors this disorder, which is actually a variant of mixed gonadal dysgenesis, must be distinguished from the other forms of male pseudohermaphroditism.