During the past year, the findings of several clinical trials have been published that have important implications for the care of patients with venous thromboembolism. These clinical trials have produced advances in the diagnosis and treatment of venous thrombosis and pulmonary embolism and in the prevention of venous thromboembolism in high-risk patients. In patients with clinically suspected pulmonary embolism, the value and limitations of ventilation-perfusion lung scanning have been established, and it is now accepted that objective tests for deep vein thrombosis have an important role. There have been important advances also in the diagnosis of deep vein thrombosis; these advances include the finding that impedance plethysmography is effective in pregnant symptomatic patients and the development of an objective technique for Doppler ultrasound. The optimal duration of initial intravenous heparin treatment of established thrombosis has been determined. In the prevention of venous thromboembolism, the effectiveness of sequential intermittent compression in patients having hip replacement has been established, and further data on the effectiveness of low-molecular-weight heparin in high-risk patients have become available.