The diagnosis and management of 159 episodes of venous thrombosis or embolism in 133 patients is discussed in the light of our experience and the reports of others. Treatment primarily consisted of continuous intravenous heparinization for 7 to 14 days with surgical methods reserved for the few where this was contraindicated or had failed. Six patients died before treatment could begin. Three percent of all treated patients died. The secondary embolism rate for 132 courses of heparin sodium was 3% with 1.5% deaths. Bleeding requiring cessation of therapy occurred in 1.3%, but none died due to this. The ten venous thrombectomies in nine patients and six inferior vena caval interruptions are discussed in relation to the indications for surgical management. Principles of managements are proposed and questions requiring solution are outlined.