Hormonal contraception, through suppression of ovarian activity or endometrial proliferation, can be used to treat and prevent a range of gynaecological disorders. There is evidence to support the effectiveness of the levonorgestrel intra-uterine system (LNG-IUS), combined oral contraceptive pill (COC) and progestogen-only injectable depot-medroxyprogesterone acetate for treating heavy menstrual bleeding and dysmenorrhoea. COCs are also an effective treatment for acne and hirsuitism, and may lessen the symptoms of premenstrual syndrome. There is good evidence that COCs can significantly reduce the risk of both ovarian and endometrial cancer. There is also some evidence that COCs may prevent ovarian cysts, endometrial hyperplasia and fibroids. The LNG-IUS may be used as endometrial protection in women using hormone replacement therapy or tamoxifen. This chapter will deal with the evidence for both treatment and prevention of a range of gynaecological disorders of different hormonal contraceptive methods.