Infection is a leading cause of mortality in hematology. Although data on nosocomial infections are available, little is known about events falling into the broader category of healthcare-associated infections. Our aim was to evaluate the incidence and causes of healthcare-associated infections in hematology patients, comparatively with nosocomial infections. Using predefined criteria, we classified 223 infectious episodes in 137 patients for their association with healthcare and nosocomial occurrence. Of the 223 infectious episodes, 204 (91%) were healthcare associated, 94/223 (42%) were also nosocomial, and 9% were community-acquired. Healthcare-associated infections should be preferred to nosocomial infections--which underestimates half of the healthcare-associated infections--as quality indicators for preventive programs.