III. Setting: The 19-bed medical ICU in a 1,400-bed university-affiliated urban teaching hospital. IV. Patients: Between January 2000 and December 2003, all patients admitted to the medical ICU were surveyed prospectively for the development of catheter-associated bloodstream infection. V. Intervention: A mandatory education program directed toward ICU nurses and physicians was developed by a multidisciplinary task force to highlight correct practices for the prevention of catheter-associated bloodstream infection. The program consisted of a 10-page self-study module on risk factors and practice modifications involved in catheter-related bloodstream infections and in-services at scheduled staff meetings. Each participant was required to complete a pretest before reviewing the study module and an identical test after completion of the study module. Fact sheets and posters reinforcing the information in the study module were also posted throughout the ICU. VI. Measurements and main results: Seventy-four episodes of catheter-associated bloodstream infection occurred in 7,879 catheter-days (9.4 per 1,000 catheter-days) in the 24 months before the introduction of the education program. Following implementation of the intervention, the rate of catheter-associated bloodstream infection decreased to 41 episodes in 7,455 catheter days (5.5 per 1,000 catheter-days) [p = 0.019]. The estimated cost savings secondary to the decreased rate of catheter-associated bloodstream infection for the 24 months following introduction of the education program was between $103,600 and $1,573,000. VII. Conclusions: An intervention focused on the education of health-care providers on the prevention of catheter-associated bloodstream infections may lead to a dramatic decrease in the incidence of primary bloodstream infections. Education programs may lead to a substantial decrease in medical-care costs and patient morbidity attributed to central venous catheterization when implemented as part of mandatory training. Central venous catheters are commonly employed in the management of critically ill patients. Primary bloodstream infections resulting from central venous catheterization are a common cause of excess morbidity, mortality, and medical-care costs in the ICU setting.1234567 The National Nosocomial Infections Surveillance system for the Centers for Disease Control and Prevention (CDC) reports a catheter-associated bloodstream infection rate of 5.7 per 1,000 catheter days.8 Mortality attributable to catheter-associated bloodstream infections has been estimated to be as high as 35%, and length of hospital stay is consistently increased in published reports among infected patients.4910111213141516 The excess hospital costs associated with an episode of catheter-associated bloodstream infections has been estimated to range from $3,700 to $56,167.41215 Although the optimal approach to reducing hospital-associated infections is unclear, several recent studies27161718 indicate that educating health-care workers on evidence-based approaches for the prevention of these infections can decrease their rates. The CDC recommends the utilization of health-care worker education as an important element in programs aimed at the prevention of hospital-acquired infections.19 Successful education-based interventions for bloodstream infections have focused on community hospitals, teaching hospitals, and physicians-in-training.2716 Therefore, we carried out a clinical investigation to determine whether an education program could decrease the rate of catheter-associated bloodstream infection in the medical ICU of a teaching hospital.