Interruption of the inferior vena cava is usually performed with either external clipping or transvenous filter placement. For patients unable to tolerate general anesthesia and laparotomy, the advantages of transvenous filters rather than clips are obvious. However, for some patients, the use of either clips or filters is possible. In general, retrospective observational studies of inferior vena caval interruption have not adequately accounted for baseline patient characteristics such as age, presence of cancer, and history of prior venous thromboembolism. These confounding factors can independently affect subsequent rates of both recurrent embolism and overall mortality. A comparative, controlled, prospective evaluation of inferior vena caval clipping versus transvenous filter placement among patients who are appropriate candidates for either procedure has not been undertaken. It is suggested that, among patients with good long-term prognoses, a randomized controlled trial would be necessary to help determine whether clipping or transvenous filter placement is more efficacious.