During the post-menarcheal years several kinds of menstrual disorders can be observed, such as abnormal uterine bleeding, primary and secondary dysmenorrhea, premenstrual syndrome, primary and secondary amenorrhea and oligomenorrhea. Abnormal uterine bleeding and especially the subtype of dysfunctional uterine bleeding is the most urgent gynecological problem during adolescence, while dysmenorrhea is the most frequent one for which adolescents and their parents refer to a physician. Normal menstrual cycle physiology as well as definitions of all the above menstrual disorders is briefly mentioned before going on with dysfunctional uterine bleeding and dysmenorrhea.