Problems associated with menstruation affect 75% of adolescent females and are a leading reason for visits to physicians. This chapter begins with a review of the timing and characteristics of normal menstruation during adolescence. It then discusses the evaluation and management of adolescents with amenorrhoea, dysmenorrhoea and abnormal uterine bleeding. An approach to adolescent amenorrhoea is presented that utilizes primary versus secondary amenorrhoea, delayed versus normal pubertal development, and the presence or absence of hyperandrogenism as nodal points for decision making. The differential diagnosis of dysmenorrhoea and the management of primary dysmenorrhoea and endometriosis are reviewed. The section on abnormal uterine bleeding contrasts anovulatory dysfunctional uterine bleeding (DUB) with bleeding secondary to problems of pregnancy, uterine pathology, exogenous hormone use and systemic bleeding disorders.