This study evaluated whether the branched-chain amino acid-to-tyrosine ratio (BTR) is a prognostic predictive factor in patients with liver cirrhosis by determining the relationship of the BTR with event-free survival in a retrospective, observational cohort study. The medical records of patients with liver cirrhosis who visited our institution from February 2000 to May 2012 were examined. Events due to liver cirrhosis were defined as death, worsening of esophageal and/or gastric varices, hepatocellular carcinoma, and liver failure. The primary endpoint was the period from the date of BTR measurement until the first onset of these events. Event-free survival was compared between patients with BTR ≥ 4 and BTR < 4. Relationships between the BTR and other factors predicting prognosis were also examined. Event-free survival was evaluated in patients with and without branched-chain amino acid supplementation using propensity score matching. Significantly longer event-free survival was found in liver cirrhosis patients with BTR ≥ 4 (n = 425) compared with those with BTR < 4 (n = 105), and the BTR was associated with liver cirrhosis events. The BTR showed significant relationships with other predictive factors evaluated. In subcohorts matched by propensity score, branched-chain amino acid supplementation significantly improved event-free survival in patients with BTR <4. The BTR is clinically useful for predicting prognosis in liver cirrhosis patients. BCAA supplementation may be beneficial in those with BTR < 4.