Long-term use of hormonal therapy is controversial in many clinical settings. Estrogens and progestins are known to have profound systemic and cellular effects, many of which are not evident for many years. Oral contraceptives contain significant amounts of these hormones which affect the reproductive organs. A review of breast structure and tissue characteristics, as well as the effects of these hormones on breast tissue, is presented. Emphasis is placed on the need to be cognizant of these similarities and breast tissue receptivity to hormones when considering oral contraceptive therapy.