Kimray-Greenfield filters were inserted percutaneously into the inferior vena cava (IVC) in 57 patients. Thirty-six were placed from the right femoral vein, 14 from the left femoral vein, and seven from the right internal jugular vein. There were no deaths or major complications and only six minor complications. Inferior vena cavography was done before filter insertion in all cases. Cavography is vital to determine feasibility of filter insertion, route of insertion, and filter location; pertinent findings include caval size, presence or absence of clot in the IVC or iliac veins, and position of the renal veins. The guide wire provided with the standard filter introduction set has a tendency to catch on the filter as the wire is withdrawn. A stiff wire with a straight, tapered, floppy tip was substituted. The femoral approach is preferred when it is feasible. Though there was only one known occurrence of femoral vein thrombosis at the filter insertion site, other cases may have occurred and may not have been detected. If the frequency of this complication proves to be significant, the preferred route for filter insertion may have to be reconsidered.