Transgenderism occurs when an individual's gender identity conflicts with the individual's biological sex. A variety of methods may be used in order to reconcile this disparity in transgender individuals including psychological counseling, cross-sex hormone therapy and sex reassignment surgery. The most important role for pharmacists in the treatment of transgender patients is in dispensing hormonal medications for cross-sex treatment. Hormone therapy may be used to suppress characteristics of the patient's biological sex as well as to induce development of characteristics that correlate with the patient's gender identity. In male-to-female (MtF) transgender patients, the most commonly used medications include agents which suppress testosterone such as mineralocorticoid receptor antagonists and gonadotropin-releasing hormone (GnRH) agonists. This is in addition to estrogen therapy, which causes feminization. By far the most commonly used medication for female-to-male (FtM) transgender patients is testosterone to induce masculinization. Medroxyprogesterone or GnRH agonists may also be used in FtM patients to suppress female characteristics. Pharmacists should be aware of the risks associated with cross-sex hormone therapy in transgender patients as well as the side effects and monitoring required for these therapies. Pharmacists may also play a role in being able to recognize signs of appropriate feminization or masculinization in MtF and FtM patients.