Infection, thrombosis, and stenosis are among the most frequent complications associated with blood-contacting catheters. These problems are usually related to surface properties of the base catheter material. Surface treatment processes, such as ion implantation and ion beam assisted deposition (IBAD) and microdomain structured surfaces, can be used to mitigate such complications. This study evaluated silver coated and implanted large bore catheters used for extracorporeal detoxification. In a 186 patient prospective study, 225 large bore catheters were inserted into the internal jugular or subclavian veins. Eighty-five surface-treated catheters (Spi-Argent, Spire Corporation, Bedford, MA, USA) and 28 catheters with surface treatment (Spi-Silicone, Spire Corporation) were inserted in 90 patients. One hundred and twelve untreated catheters placed in 96 patients served as controls, After removal, the catheters were cultured for bacterial colonization using standard microbiologic assays. They also were examined using a scanning electron microscope (SEM). Bacterial colonization was observed in 8% of the treated catheter compared with 46.4% of untreated catheters. The SEM investigations showed all treated catheters to possess low thrombogenicity. Catheters with microdomain structured surfaces showed same results in preliminary observation. The surface treatments of the large bore catheters can be used to improve thrombus and infection resistance of blood contacting catheters.