One of the most common gynecological consultations is for abnormal uterine bleeding. The condition accounts for up to 70% of new gynecological consultations in perimenopausal women. After excluding organic causes, the mainstay of treatment is medical, most usually with progestogen supplementation. However, treatment should be personalized depending on the patients age, desire for contraception or fertility, etc. In many cases in addition to progestogen, estrogen is often required to build the endometrium, particularly in cases of a thinned endometrium due to ovarian dysfunction. Thus, the choice of progestogen needs to take into account the estrogenic, antiestrogenic, androgenic or anti-androgenic effects of the particular progestogen. In this chapter the pathophysiology, diagnosis and the resulting medical treatments of abnormal uterine bleeding are outlined.