In recent years, dramatic changes in health care systems have shifted much of the care of sick individuals from hospitals to the community. Consequently, infections traditionally classified as community-acquired or hospital-acquired infections cannot now be readily classified into either category. We thus propose a new classification based on a wider spectrum of acquisition. A total of 1028 episodes of bloodstream infection (BSI) were divided into 5 categories: true community-acquired infections (370 episodes [36%]), infections in recently discharged patients (110 [11%]), infections associated with invasive procedures performed just before or at the time of admission (56 [5%]), infections in patients admitted from nursing homes (68 [7%]), and hospital-acquired infections (424 [41%]). Thus, 234 (39%) of the 604 bloodstream infections traditionally defined as community acquired were reclassified into 3 newly defined groups, each of which has distinct epidemiologic, clinical, and bacteriologic characteristics, as well as distinct antimicrobial susceptibility profiles. There is a conceptual and practical need for such a new classification.