Allogeneic packed red blood cells (PRBCs) suppress immunity and influence outcomes. The influence of blood on the risk of infection and death may be related to the duration of storage. We sought to determine whether blood storage duration was associated with infection or death in a large cohort of injury victims. We reviewed a cohort of trauma patients transfused at least 1 U of PRBCs within 24 h of admission to a level 1 trauma center. The outcomes of interest were complicated sepsis and mortality. We compared the amount of older blood (>14 days storage) given to patients who did or did not develop the outcomes of interest using univariate and multivariate methods. A total of 820 patients were included. Patients who died (n = 117) received more units of older blood than those who lived (5 U [inter quartile range {IQR}, 2-9] vs. 3 U [IQR, 2-6]; P < 0.001). Patients with complicated sepsis (n = 244) received a greater volume of older blood than those without complicated sepsis (6 U [IQR, 2-10] vs. 3 U [IQR, 1-5]; P < 0.001). After adjusting for clinical factors, including the total amount of blood transfused, patients receiving greater than or equal to 7 U of older blood had a higher risk of complicated sepsis than patients receiving 1 or fewer units (odds ratio, 1.9; P = 0.03). The risk for complicated sepsis and death in trauma victims who are transfused blood is high. The amount of older blood transfused is associated with complicated sepsis. Although the best strategy to minimize the effects of allogeneic blood is to avoid unnecessary transfusions, it may be particularly important to avoid transfusing multiple units of older blood.