OBJECTIVE: To evaluate the efficacy of triple-lumen central venous catheters coated with a combination product of chlorhexidine and silver sulfadiazine (CSS) in reducing the incidence of local catheter infection and catheter-related bacteremia. DESIGN: Randomized, controlled trial. SETTING: The surgical intensive care units in a university hospital. PATIENTS: All patients who needed central venous catheterization were randomized to receive either an uncoated triple-lumen catheter (n = 157) or a catheter coated with CSS (n = 151). MAIN OUTCOME MEASURE: Catheters were removed when no longer needed or suspected as a cause of infection. The tip and a 5-cm segment of the intradermal portion of the catheter were cultured semiquantitatively. Blood cultures were obtained when clinically indicated. The remaining segment of catheters coated with CSS were cut and incubated on an agar plate with strains of Staphylococcus aureus and Enterococcus. Zone of inhibition was determined 24 hours later. Data were analyzed by survival and logistic multivariate regression methods. RESULTS: Catheters coated with CSS were effective in reducing the rate of significant bacterial growth on either the tip or intradermal segment (40%) compared with control catheters (52%; P = .04). However, there was no difference in the incidence of catheter-related bacteremia (3.8% [uncoated] vs 3.3% [coated]; P = .81). In vitro activity of catheters with CSS against S aureus was evident up to 25 days but activity against Enterococcus dissipated more quickly over time and was absent by day 4. The most common colonizing organisms were coagulase-negative staphylococcus and enterococcus. Variables that were associated with a significant amount of growth on the tip or intradermal segment were a duration of catheterization of longer than 7 days, jugular insertion site, and the absence of a CSS coating. The use of a guidewire when the catheter was removed was associated with a lower risk of significant bacterial growth. CONCLUSIONS: The use of CSS reduces the incidence of significant bacterial growth on either the tip or intradermal segments of coated triple-lumen catheters but has no effect on the incidence of catheter-related bacteremia. In this patient population, catheters coated with CSS provide no additional benefit over uncoated catheters.