Lymphedema are primary (lower limb) or secondary for the upper limb after treatment of breast cancer. Genetic research allows to explain better pathophysiology of lymphedema. Lymphoscintigraphy is the main imaging technique for lymphedema. Venous or compressive etiologies may be first excluded. Treatment of lymphedema includes decongestive physiotherapy: manual lymph drainages, bandages, elastic stockings, exercises, skin care to avoid infections. Other treatments may be associated: weight loss, drugs (procyanidolic oligomers), surgery for genital lymphedema, pneumatic compression pumps for lymphovenous insufficiency. (C) 2002 Editions scientifiques et medicales Elsevier SAS.