Objective: Few studies have shown that aged packed red blood cells (RBC) transfusion negatively influenced the outcome of ICU patients, probably related to storage lesions which could be decreased by leukodepletion of RBC. The purpose of this study was to evaluate the impact of aged leukodepleted-RBC pack, on the outcome of ICU patients. Design: Retrospective, observational, cohort study in a Medical Intensive Care Unit. Patients: Consecutive patients admitted during the years 2005 and 2006, and requiring a transfusion. We recorded patient's demographic data, number of RBC unit and age of each RBC, length of ICU, mortality during ICU stay. Results: Five hundred and thirty-four patients were included with global mortality was 26.6%, length of stay in ICU six days (3-14) and SAPS II 48 (35-62). RBC equaling to 5.9 were transfused per patients (22.7%