Background: Excessive use of blood components during liver transplantation should be avoided because it has been associated with poor outcomes and it may stress blood bank resources. Study design and methods: To determine preoperative predictors of excessive transfusion requirements in patients undergoing liver transplantation, the clinical records of 126 consecutive adult patients undergoing primary liver transplantation were retrospectively reviewed. Outcome variables included number of red blood cells (RBCs), plasma, and plateletpheresis components intraoperatively transfused. Univariate analyses of the following predictor variables were performed: recipient age, sex, ethnicity, height/weight, Model for End Stage Liver Disease score, year of transplant, previous abdominal surgery, hepatoma, wait-list time, standard recipient laboratory values obtained immediately before transplantation, cold ischemia time, donor age, sex, and height/weight. Multivariate analysis using logistic regression was used to build a model that best predicted how many blood components should be available before transplant. Results: Donor age of more than 50 years old (odds ratio [OR], 2.8 95% confidence interval [CI], 1.3-6.0), and recipient serum creatinine (SCr) level of more than 1.3 mg/dL (OR, 3.8 95% CI, 1.6-8.9) were the only variables found to be predictive of RBC use in multivariate analysis. This model accurately predicted the use of more than 10 units of RBCs 79% of cases. Having both adverse factors present resulted in using more than one box in 80% of cases as compared to 44% of cases where only one or no adverse factor was present (p = 0.002). Further analyses showed a direct correlation between the number of RBCs transfused and plasma (r = 0.93) and plateletpheresis components (r = 0.74) transfused. [Corrections added after online publication 22-Jul-2009: OR updated from 3.8 to 2.8; CI from 1.6-8.9 to 1.3-6.0; OR from 2.8-3.8.] Conclusion: Liver donor's age and recipient's SCr are important in preoperatively predicting blood use during liver transplantation.