Because of the chronic shortage of liver donors, hepatologists are required to prolong the liver transplant waiting period by preserving the hepatic reserve of scheduled recipients. This study examined the effectiveness of oral branched-chain amino acids (BCAAs), using outcome markers indicating pretransplant hepatic reserve. Fifty-six consecutive eligible patients with Child class A cirrhosis without major complications were randomly assigned to receive oral BCAA granules (12.45 g/day) for least 1 year or no BCAAs. Differences between groups in the Model for End-Stage Liver Disease (MELD) score, Child-Turcotte-Pugh (CTP) score, asialoscintigraphic clearance index (CI), and complications were examined. Of 50 remaining patients, 27 received BCAAs, and 23 received no BCAAs (mean duration, 3.2 years). The mean annual changes in the MELD score, CTP score, and asialoscintigraphic CI were smaller in the BCAA group than in the control group (-0.06 +/- 0.23 versus 0.10 +/- 0.40, P = 0.024, 0.06 +/- 0.30 versus 0.30 +/- 0.48, P = 0.037, and 0.00 +/- 0.02 versus 0.02 +/- 0.04, P = 0.040, respectively). The mean annual changes in the serum total bilirubin and the serum albumin in the BCAA group were better preserved than those in the control group (-0.07 +/- 0.20 versus 0.12 +/- 0.18 mg/dL, P < 0.001, and 0.07 +/- 0.13 versus -0.02 +/- 0.19 g/dL, P = 0.005, respectively); other laboratory variables were not significant. The incidence of overall major cirrhotic complications was lower in the BCAA group than in the control group [14.8% (4 of 27 patients) versus 30.4% (7 of 23 patients) at 3 years, P = 0.043]; only ascites was significant individually. In conclusion, early interventional oral BCAAs might prolong the liver transplant waiting period by preserving hepatic reserve in cirrhosis.