Health care–associated infections (HAIs) remain a major contributor to preventable morbidity and mortality in hospitalized patients, despite some progress in combating certain infections. This economic analysis combined a systematic review of estimates of costs attributable to HAIs with HAI incidence data to project hospitals' total financial burden caused by these infections in adult inpatients. The authors conclude that the 5 most common HAIs result in an annual cost to the health care system of nearly $10 billion. Since the majority of HAIs are considered preventable, this finding implies that considerable savings could be achieved through more rigorous HAI prevention efforts. Although the study is limited by the heterogeneous methods of determining costs used in the original studies, other studies have shown a relatively strong business case for hospitals to invest in efforts to prevent HAIs.