Liver dysfunction is frequent before allogeneic stem cell transplantation (allo-SCT). However, its characteristics and impact on transplantation outcomes are uncertain, especially in the reduced-intensity conditioning (RIC) setting. We analyzed 455 patients receiving an allo-SCT in 3 Spanish centers. Pretransplantation aspartate aminotransferase (AST), alanine aminotransaminase (ALT), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (AP), total bilirubin, and international normalized ratio were analyzed. Pretransplantation liver function test abnormalities were found in 94 (22%) patients. The most frequent cause of pretransplantation liver dysfunction was isolated elevation of GGT/AP (n = 49, 53%). Patients with high bilirubin levels before allo-SCT showed higher 4-year nonrelapse mortality (4y-NRM) (hazard ratio [HR] 2 [95% confidence interval [CI] 1.1-3.8] P = .02) and patients with high GGT levels showed higher 100-day NRM and lower 4-year overall survival (OS) (HR 3.4 [95% CI 1.8-6.7] P < .001, and HR 2 [95% CI 1.4-3], P = .001), respectively. High levels of transaminases did not influence on survival or mortality. In conclusion, hepatic dysfunction before allo-SCT is frequent and has an impact on transplantation outcomes. The best indicator of liver dysfunction still has to be determined.