Objective To describe off-label utilization of erythropoietic agents in ICU patients.Methods A retrospective, observational study design was used to describe off-label utilization of erythropoietin alfa and darbepoetin alfa by 91,357 patients in the ICU during January 2002- June 2004 at 433 U.S. hospitals. Results Approximately 62% of patients received erythropoietic agents off-label in the ICU compared to 49% in the non-ICU population. Off-label use in the ICU was more likely in teaching hospitals, in larger sized hospitals, in females, for certain physician specialties, and in different regions of the U.S., The longer the hospital stay, the less likely off-label prescribing occurred. ConclusionsOff-label use of erythropoietic agents was common in the ICU. Multiple factors affected off-label use in the ICU although no single one was dominant.