Background The aim of this study was to investigate the possible effect of somatostatin on the liver function of recipients undergoing living donor liver transplantation.Methods Forty recipients were randomized into group A (n=20) and group B (n=20). Recipients in group A received no somatostatin whereas somatostatin was administrated for recipients in group B perioperatively. Liver function, the plasma concentration of endothelin-1 and nitric oxide, the intragraft expressions of endothelin-1 and inducible nitric oxide syntheses at 2 hours after declamping of the portal vein were compared between the two groups.Results Compared to group A, alanine transaminase values in group B were significantly reduced at 2 hours after portal vein declamping, at the end of the operation and postoperation day 1 (P ＜0.05), whereas aspartate aminotransferase values in group B decreased at 30 minutes after portal vein clamping, at 2 hours after portal vein declamping and at the end of the operation (P ＜0.05). Total bilirubin values in group B were reduced significantly at 2 hours after portal vein declamping and at the end of the operation when compared to group A (P ＜0.05). Intragraft expression of endothelin-1 was significantly downregulated at 2 hours after declamping of the portal vein accompanied with a reduction of plasma concentration of endothelin-1 in the peripheral blood (P ＜0.05).Conclusions Somatostatin had a protective effect on liver function during the early phase after declamping of portal vein for recipients undergoing living donor liver transplantation, and the possible mechanism might be partially attributed to the downregulation of endothelin-1.