OBJECTIVE Several reports have demonstrated the efficacy of inferior vena cava filter (IVCF) placement with intravascular ultrasound guidance (IVUS). The majority of these procedures,however, have been done in concert with contrast venography and/or fluoroscopic guidance. The purpose of this report was to evaluate the potential for bedside IVCF placement with "real-time" IVUS guidance only. METHODS In a phase I trial, 10 patients underwent IVUS interrogation of the IVC for diameter measurements and localization of the renal veins. Contrast venography verified the IVUS findings prior to filter deployment. In a phase II trial, another 35 patients underwent intensive care unit bedside placement of an IVC filter with only "real time" IVUS guidance using a double puncture technique in the same femoral vein. All patients underwent color-flow ultrasonography of the femoral veins after filter placement to rule out post procedure femoral vein thrombosis and plain radiographs of the abdomen to identify filter location. RESULTS In the phase I trial, all filters were placed within 15 mm of the most inferior renal vein identified by IVUS. There were no complications, and successful filter placement was verified by contrast venography. In phase II, 33 IVCFs were placed without complications at approximately the L2 level by plain radiograph. One patient had an IVCF deployed in the common iliac vein, which necessitated placement of an uneventful second IVCF at the infrarenal location by IVUS. This same patient had a femoral deep venous thrombosis identified by postoperative duplex ultrasonography. A second patient had IVC thrombus identified by IVUS, and placement was performed with contrast venography in the fluoroscopy suite. IVC measurements ranged from 18-28 mm in diameter. CONCLUSIONS IVUS accurately measures the IVC diameter and localizes the renal veins, allowing for exact placement of IVCFs. IVUS further avoids the need for contrast agents and for transport of critically ill patients. Bedside insertion of an IVcF with IVUS guidance is simple, safe, and accurate. Further assessment of this technique is warranted.