After a two year analysis of a thirty-one-year-old eunuchoid, who before and during analysis had been treated endocrinologically, the author concludes that: (1) the psychosexual development of his childhood revealed a normal Oedipus complex with no great deviation from the ordinary; (2) the weakness of his libinal drives after puberty made him unable to keep pace with other boys in sexual development and in dealing with his previous conflicts, especially with his castration fear; (3) old methods of defence against masculinity, such as passive homosexual attitudes, continued to operate after he had attained physical sexual maturity endocrinologically. These defences had to be resolved analytically before he could accept heterosexuality.