Healthcare-associated infections (HAIs) are considered to be the greatest risk patients face in the hospital environment. HAIs can occur in any patient care setting, but infections in hospitalized patients account for the vast majority of HAIs. Hospitalized patients are additionally susceptible to experiencing serious consequences of HAIs due to comorbid illnesses. According to estimates from the Centers for Disease Control and Prevention (CDC), up to two million patients (nearly one in 20 hospitalized patients) experience a healthcare-associated infection every year in the U.S., leading to approximately 88,000 deaths and $4.5 billion in extra costs per year. Moreover, the incidence of HAIs appears to have increased over the last three decades, despite the fact that the majority of HAIs are thought to be preventable. Efforts to monitor and prevent HAIs have existed for decades. These efforts have followed the public health methodology of surveillance and prevention. The effectiveness of such methods was provided by the Study of the Effectiveness of Nosocomial Infection Control study, which demonstrated that hospitals with structured infection control programs achieved sustained reductions in HAI rates, whereas hospitals with less comprehensive programs saw increased infection rates. The growing focus on improving patient safety over the past few years has catalyzed even greater efforts to curb HAIs. Public reporting of infection rates has been proposed as a means of educating patients and encouraging preventive efforts; currently, six states require reporting of HAIs, and legislation requiring some type of reporting has been proposed in the majority of states. Within the hospital, surgical site infections (SSI) and three types of infections common in intensive care unit patients are particularly prevalent-central-line associated bloodstream infections, ventilator-associated pneumonia, and catheter-associated urinary tract infections. Together, these infections account for more than 80 percent of all HAIs. In this report, we systematically review the evidence supporting quality improvement strategies to reduce the incidence of these key healthcare-associated infections. We intend to identify strategies that successfully increase adherence to effective preventive practices for each of these infections and reduce infection rates. Our specific research questions are: 1. Do quality improvement strategies increase adherence to evidence-based preventive interventions for healthcare-associated infections? 2. What are the critical components of effective QI strategies? 3. What are the limitations of current research in this field, and what areas require further study? We defined a "preventive intervention" as a specific infection control practice that has been demonstrated to reduce the incidence of a HAI. To identify target preventive interventions, we reviewed the CDC guidelines for prevention of surgical site infection, prevention of intravascular catheter-related infections, prevention of healthcare-associated pneumonia, and prevention of catheter-associated urinary tract infection. Hand hygiene was identified as an important preventive intervention for all HAIs. The disease-specific target preventive interventions we identified are as follows: Surgical site infection: appropriate perioperative antibiotic prophylaxis (including appropriate antibiotic selection, timing, and duration), perioperative glucose control, and decreasing shaving of the operative site; Central line-associated bloodstream infection: adherence to maximal sterile barrier precautions, use of chlorhexidine for skin antisepsis, and avoidance of femoral catheterization; Ventilator-associated pneumonia: semirecumbent patient positioning and daily assessment of readiness for ventilator weaning; Catheter-associated urinary tract infection: reduction in unnecessary catheter use and adherence to aseptic catheter insertion and catheter care.