We studied the prognostic significance of antiphospholipid antibodies for recurrence of venous thromboembolism (VTE), in 71 patients admitted for acute VTE (deep-vein thrombosis or pulmonary embolism) in a single internal medicine unit. Lupus anticoagulant (LA), antibodies directed against beta 2-glycoprotein I (beta 2GPI) and antibodies against both beta 2GPI and a mixture of phospholipids (cardiolipin, phosphatidylserine and phosphatidic acid) (APAs) were measured. The patients were followed-up (mean 4.9 years) to determine the time to the next VTE. We found LA in nine patients, anti-beta 2GPI antibodies in seven patients and APAs in six patients. The cumulative risk of recurring VTE was higher in patients with beta 2GPI-binding antibodies (hazard ratio 12.6, 95% CI 1.5-104.9; p = 0.0029). The risk associated with APAs was 11.5 (95% CI 1.3-98.9; p = 0.0049) and that for LA was 3.7 (95% CI 0.9-15.6; p = 0.055). The risk of VTE recurring was higher both in patients with antibodies directed against beta 2GPI, and in patients with antibodies directed against beta 2GPI and a mixture of phospholipids, than in patients without these antibodies.