• Five commonly used prostheses were compared for susceptibility to bacteremic infection: US Catheter and Instrument Co (USCI) Ultralight weight knitted Dacron, USCI Sauvage filamentous velour Dacron, Meadox Microvel double velour knitted Dacron, polytetrafluoroethylene (PTFE)-lmpra, and PTFE-Goretex. We used 6-mm diameter grafts to replace 4-cm segments of the abdominal aorta in 150 mongrel dogs. Fifteen dogs were used for each graft type and each healing interval: three and six months posttransplantation. At the appropriate time after implantation, an intravenous infusion of 108 organisms of Staphylococcus aureus was administered to the ten experimental dogs in each graft type; five dogs of each graft type served as sterile controls. Three weeks later, the grafts were aseptically removed, inspected for the completeness of neointimal healing, and cultured for bacteria. At three months, the Sauvage graft achieved the lowest infection rate (10%) with the highest incidence of complete neointimal lining (71%). In the six-month series, there were no statistical differences between the knitted Dacron prostheses, but all Dacron grafts were superior to the PTFE grafts with regard to susceptibility to bacteremic infection and completeness of intimal lining. (Arch Surg 115:1379-1383, 1980)