We report a prospective, randomized, controlled clinical trial to evaluate the efficacy of antibiotic-bonded catheters in reducing the incidence of intravascular catheter-related infections. Ninety-three central venous catheters and 85 arterial catheters were studied in the surgical intensive care unit. Study catheters were pretreated with the cationic surfactant tridodecylmethylammonium chloride. The anionic antibiotic, cefazolin, was bonded before insertion of the catheters by immersing them in a 50-mg/mL solution. Fourteen percent of the 81 catheters in the control group were infected, compared with 2% of the 97 antibiotic-bonded catheters. Staphylococcus epidermidis was the most common organism obtained. There was no significant difference in the number of colonized or clinically inflamed catheter insertion sites. None of the 100 antibiotic immersion solutions yielded anything on microbiologic culture. We conclude that antibiotic bonding is an efficient, safe, and cost-effective method of reducing intravascular catheter infection in patients who are in intensive care units.