Few natural history studies are available which describe long-term outcomes after venous thromboembolism. However, symptomatic deep-vein thrombosis (DVT) of the lower extremities carries a high risk for recurrent venous thromboembolism that persists for many years. This risk is higher among patients with permanent risk factors including inherited abnormalities of hemostasis than among patients who have suffered trauma or who are postoperative. The development of recurrent ipsilateral DVT carries a high risk for severe post-thrombotic syndrome, an otherwise rare problem in patients with a first episode of DVT adequately treated with anticoagulant drugs and wearing vascular compression stockings. Long-term survival following DVT is generally good in the absence of malignancy. Carefully designed randomized trials are needed to determine whether chronic anticoagulation can reduce further the risks of recurrent DVT and symptoms of post-thrombotic syndrome.