This review presents the diagnostic features, the pathophysiology and the available therapies for lymphedema. This disease is often able to be diagnosed by its characteristic clinical presentation, yet, in some cases, ancillary tests might be necessary to establish the diagnosis, particularly in the early stages of the disease and in edemas of mixed etiology. These diagnostic modalities are also useful in clinical studies. Available modalities include isotopic lymphoscintigraphy, indirect and direct lymphography, magnetic resonance imaging, computed tomography and ultrasonography. Lymphedema may be primary or secondary to the presence of other disease and/or to the consequences of surgery. Primary lymphedema may occur at any phase of life but it most commonly appears at puberty. Secondary lymphedema is encountered more often. The most prevalent worldwide cause of lymphedema is filariasis, which is particularly common in south-east Asia. In the USA, postsurgical lymphedema of the extremity prevails. Complications of chronic limb lymphedema include recurrent cellulitis and lymphangiosarcoma. Most patients are treated conservatively, by means of various forms of compression therapy, including complex physical therapy, pneumatic pumps and compressive garments. Volume reducing surgery is performed rarely. Lymphatic microsurgery is still in an experimental stage, although a few centers consistently report favorable outcomes.