Microbial blood infection represents a high risk for immuno-suppressed patients. Of all catheter-related infections in the bloodstream, 90% result from the use of central venous catheters, the main cause being microbial colonization at the catheter's insertion point or the catheter hub. Between January 2003 and December 2004, 102 patients received a renal transplant including 57 who received a triple-lumen central venous catheter (CVC) during the procedure. Two catheters were used: a standard polyurethane catheter placed in the jugular veina or the subclavian veina for group I, and polyurethane catheters with the AgION antimicrobial system always placed in the subclavian veina for group II. Care and maintenance of the CVCs was standardized in both groups. After catheter removal, the tips were analyzed microbiologically. Of 57 (43.9%) CVCs, 25 were found to be contaminated. In the first group 24 out of 41 CVCs (58.5%) showed bacterial growth, whereas in group II only one catheter (6.6%) had a biofilm. The most common contaminant (18 out of 25, 72%) was Staphylococcus epidermidis. In group II, two patients had positive blood cultures yet a microbiologically sterile CVC. None of the catheters with the AgION antimicrobial system had to be removed owing to local infection or intolerance. The continuous release of silver ions increases the protection against bacteria and fungi during the entire time of catheterization. Use of catheters with the AgION antimicrobial system lead to a marked reduction in catheter-associated infections of the bloodstream.