Concerns about abnormal menstrual bleeding are a common reason for women to consult a primary care physician. The first step in the evaluation is to determine the patient's ovulatory status. Women with heavy bleeding but normal ovulatory cycles should be evaluated for coagulopathies, structural lesions, and hypothyroidism. In the absence of a systemic or structural cause, menorrhagia can be treated with OCPs or NSAIDs. Intermenstrual bleeding in OCP users may be due to noncompliance or the use of low-dose pills. Encouraging patient compliance and adjustment of the estrogen dose can often solve the problem. If the patient is not on OCPs, intermenstrual bleeding is usually due to a structural or inflammatory lesion. The differential diagnosis for anovulatory bleeding is extensive. Pregnancy, systemic illnesses, and structural lesions should be ruled out by history, physical examination, and laboratory evaluation. Endometrial biopsy is indicated in patients over age 35 and younger patients with risk factors for endometrial cancer, such as chronic anovulation and obesity. Dysfunctional uterine bleeding is a nonspecific term for abnormal uterine bleeding in the absence of systemic or structural disease. It is usually associated with anovulation. Adolescents frequently have dysfunctional uterine bleeding owing to immaturity of the hypothalamic-pituitary-ovarian axis. Perimenopausal women have an increased incidence of irregular bleeding secondary to decreased estrogen production by the ovary. Obesity, polycystic ovary syndrome, stress, crash diets, and vigorous exercise can all disrupt normal ovulatory function. Treatment options for dysfunctional uterine bleeding include oral contraceptives, cyclic progesterone, or hormone replacement with estrogen and progesterone. Patients with structural lesions or those who do not resume normal withdrawal bleeding patterns on hormone therapy should be referred to a gynecologist for further evaluation and treatment.