&NA;The first implantable endovascular devices for the treatment of venous thromboembolism (VTE) were the Mobin‐Uddin Umbrella (1969) and the Kimray‐Greenfield filter (1973). Current vena cava filters (VCFs), like the initial devices, filter and trap emboli from distal venous beds that may embolize to the lungs. Their design promotes caval interruption without occluding venous flow. Percutaneous catheter deployment of devices usually within the inferior vena cava has facilitated their placement of VCFs. Increased experience with this adjunct to the management of VTE has shown favorable safety and efficacy profiles. Ease of placement, familiarity with these devices, and favorable efficacy profiles have all been implicated for the current increase in VCF placement. Many authors have advocated their use in a number of clinical settings that would not be considered typical indications, and many of these indications remain controversial. Standard indications for VCF insertion in patients with VTE include (1) contraindications to anticoagulant therapy; (2) failure of anticoagulant therapy; (3) free‐floating proximal thrombi; (4) surgical embolectomy or endarterectomy; (5) chronic recurrent pulmonary embolism with pulmonary hypertension. Current “evolving” indications and practices include (1) alternative locations, including both the suprarenal inferior vena cava and superior vena cava; (2) primary treatment of VTE in patients without contraindications to anticoagulation; (3) primary prophylaxis in patients historically at high risk for VTE; and (4) the use of temporary VCFs. Significant questions regarding improvement in survival, cost‐effectiveness, and long‐term safety and efficacy compared with anticoagulation remain unanswered.Clin Pulm Med 2000;7(1):41‐47