Abnormal uterine bleeding is a common entity and in spite of this its treatment can be complex. Clinical evaluation of these patients is extremely important to determine if the cause is organic or if it can be classified as a dysfunctional uterine bleeding in order to manage the patient appropriately. For this purpose the patient has to be questioned about the bleeding pattern and should be initially stratified as pre, peri or postmenopausal. This module describes the most common causes of abnormal uterine bleeding, the diagnostic tests to be ordered for classification purposes and some guidelines to treat these patients. An algorithm is presented for the evaluation of the for classification purposes patient with this condition.