The provision of hormone therapy, both estrogens and antiandrogens, to adult transgender females is well within the scope of practice of the obstetrician gynecologist. The goal is to induce feminizing changes and suppress previously developed masculinization. Estrogens in sufficient doses will usually achieve both goals with augmentation by antiandrogens. The primary short-term risk of estrogens is thrombosis, but long-term risk in transgender females is unclear. Optimal care requires pretreatment education and assessment, individualized dosing, ongoing routine monitoring, and standard breast and prostate cancer screening.