Deep vein thromboses (DVT), which are serious because of their associated risk of pulmonary embolism and troublesome due to the possible development of a post-phlebitic syndrome, require rigorous management. However, the diagnosis is facilitated by Doppler ultrasound and treatment by low molecular weight heparins (LMWH) is simple to administer and follow. It is therefore logical to propose out patient treatment, provided certain rigorous rules are respected: establishment of an objective diagnosis of DVT, as the clinical signs are relatively nonspecific, admission to hospital of patients with a haemorrhagic risk or presenting a contraindication to anticoagulants, extensive DVT (extending beyond the mid-femoral zone), floating thrombus, patients with moderate signs may suggest pulmonary embolism. The recommended dosage for LMWH is 100 IU/kg twice a day (s.c.) (or 175 IU/kg once a day for the LMWH most recently available in France) which must be followed by oral anticoagulants for 5 months (aspirin is not sufficiently effective). Contention and rigorous clinical follow-up are obviously essential. The management of DVT is fascinating and requires coordination of several competent specialists.