Inferior vena cava filters (IVCFs) are metal alloy devices that mechanically trap fragmented thromboemboli from the deep leg veins en route to the pulmonary circulation. Filters are introduced (and in the case of retrievable filters, removed) percutaneously. Although their deployment seems of theoretical benefit, their clinical efficacy and adverse event profile are unclear because there are very few controlled and randomized data. IVCFs are most frequently used in patients with contraindications to anticoagulation and in anticoagulated patients with recurrent pulmonary embolism, but few data are available in the literature about their efficacy. The indications for filters are based largely on custom, historical practice patterns and physician preferences, and their use is increasing: more trials are needed to confirm their benefit and accurately assess their safety. The care of patients with or at risk of venous thromboembolism is as variable and challenging as the range of patients who suffer from venous thrombosis. Careful, individualized decision regarding IVCF placement will be required for many years as we strive to learn more about these devices.