Cross-sex hormone treatment is an important component in medical treatment of transsexual people. Endocrinologists are often faced with designing treatment recommendations. Although guidelines from organizations, such as the Harry Benjamin International Gender Dysphoria Association, have been helpful, management remains complex and experience guided. We discuss the range of treatment used by transsexual people, the rationale behind these, and the expectation from such treatment. Recommendations from seven clinical research centers treating transsexual people are discussed. In addition, self-reported hormonal regimens from 25 male-to-female transsexual people and five female-to-male transsexual people are reported. Finally, the potential adverse effects of cross-sex hormone treatment of transsexual people are reviewed. In light of the complexity of managing treatment goals and adverse effects, the active involvement of a medical doctor experienced in cross-sex hormonal therapy is vital to ensure the safety of transsexual people.