Every year in the United States, breast cancer is diagnosed in more than 200,000 women. Because of the prevalence of breast cancer, treatment-related sequelae are of Importance to many survivors of the disease. One such sequela is upper extremity lymphedema, which occurs when fluid accumulates in the Interstitial space and causes enlargement and usually a feeling of heaviness in the limb. Axillary surgery contributes considerably to the incidence of lymphedema, with the incidence and severity of swelling related to the number of lymph nodes removed. Lymphedema after standard axillary lymph node dissection can occur in up to approximately 50% of patients. However, the risk of lymphedema is decreased substantially with newer sentinel lymph node sampling procedures. Adjuvant radiotherapy to the breast or lymph nodes increases the risk of lymphedema, which has been reported in 9% to 40% of these patients. Management of lymphedema requires a multidisciplinary approach to minimize the effect on the patient's quality of life. This review presents an overview of the pathophysiology, diagnosis, prevention, and treatment of breast cancer-related lymphedema.