The most effective methods of preventing recurrent pulmonary embolism involve interruption of the pathway of emboli through the inferior vena cava. Of the several procedures that interrupt vana caval blood flow, percutaneous implantation of a screen filter is associated with the lowest risk and appears to be as effective as any of the other procedures in preventing recurrent emboli. This article describes the experience with 62 cases of screen filter implantation performed between 1971 and 1975. Pulmonary embolism recurred in 1.6% of the patients, and 10% of the patients developed swelling of the lower extremities that did not exist preoperatively. Inferior vena cava phlebography performed 6 to 24 months postoperatively in 25 patients showed a patent inferior vena cava in 9 patients, partial occlusion of the vana cava in 8 patients, and complete occlusion of the vena cava with extensive collateral veins in 8 patients.