Over a four year period in two institutions, 85 Kim-Ray Greenfield vena caval filters were inserted in 76 patients who have been followed for a minimum of 6 to 53 months. The most frequent indication for placement was pulmonary embolism during anticoagulant therapy. Both femoral and jugular routes were used for transvenous insertion, and fewer complications were associated with the jugular approach. Surgical mortality within two weeks of operation occurred in three patients (4%), none from recurrent embolism. Late complications included recurrent thrombophlebitis in 7% and persistent extremity edema in 12% of patients. Two patients developed recurrent embolism (2.6%) which also was seen in 2 patients after clips were placed on the vena cava above the filter after misplacement. Venacavagrams in 31 patients an average of 11 months postoperative showed patency in 30 (97%) and lysis of trapped thrombi in four patients. No episodes of migration have occurred and the filter offers the advantages of sustained patency and effective filtration without vena caval occlusion.