Migraine is much more common in women than in men, especially during the reproductive years. Furthermore, the incidence of migraine attacks depends on hormonal changes, such as those that occur during menstruation or pregnancy, or in patients who use exogenously administered hormones. This chapter describes the role of ovarian hormones (primarily oestradiol and progesterone) on neurotransmission and vascular function. Furthermore, the treatment of different forms of hormonally related headaches is discussed.