25 patients with lupus anticoagulant (LA) and a history of thrombosis are described and the cases reported in the literature with this association are reviewed. From the combined data it is concluded that the prevalence of thrombosis in patients with LA is about 30%, the thrombosis sites are the leg veins in about 66%, the cerebral arteries in 25% and the peripheral arteries in 10% of the patients. High anticardiolipin levels are associated with a higher risk, while age of less than 10 years, low prothrombin activity and a platelet count of less than 50,000/microliter is associated with a lower risk of thrombosis. Heparin and oral anticoagulants are effective in the treatment and prevention of thrombosis without untoward risk of bleeding.