Background: Studies have confirmed adverse outcome associated with transfusion of packed red blood cells (PRBCs) in trauma; however, little data are available regarding other blood product transfusion, such as fresh frozen plasma (FFP) and platelets. The objective of this study was to examine risk-adjusted outcome in trauma with stratification by blood product type. Methods: Prospective data were collected daily for 1,172 consecutive trauma patients admitted to the intensive care unit (ICU) during a 2-year period, including transfusion rates of blood products (PRBCs, FFP, platelets). Outcome assessment included infection rate, ventilator days (Vdays), ICU and hospital length of stay (LOS), and mortality. Results: Blood products were transfused in 786 (67%) patients. The study cohort had a mean age of 43 ± 21 years and Injury Severity Score (ISS) of 24 ± 13. Although the majority of patients were men, women were more likely to be transfused (p < 0.001). Mean transfusion rates of PRBCs (5.5 ± 9.6 U), FFP (5.4 ± 11.4), and platelets (3.7 ± 11.1) were high. Univariate analysis identified that blood product transfusion (any type) was associated with a significantly greater infection rate (34% vs. 9.4%; p < 0.001), hospital LOS (18.6 vs. 9 days; p < 0.001), ICU LOS (13.7 vs. 7.4 days; p < 0.001), Vdays (12.9 vs. 6.3 days; p < 0.001), and mortality (19% vs. 8.3%; p < 0.001). Multivariate analysis (risk-adjusted for severity of injury by ISS, age, sex, and race, and stratified by blood product type) confirmed that risk of infection increased by 5%, and hospital LOS, ICU LOS, and Vdays increased by 0.64, 0.42, and 0.47 days, respectively, for every unit of PRBCs given. Risk of death increased by 3.5% for every unit of FFP transfused. Conclusion: There is a dose-dependent correlation between blood product transfusion and adverse outcome (increased mortality and infection) in trauma patients.