Acute flare up of hepatitis B in noncirrhotic liver with rapid liver function deterioration is a critical condition. This flare up of hepatitis B may be subsided under medical treatments, otherwise urgent liver transplantation is needed. However, the necessity of urgent liver transplantation is hard to decide. In this institute, the indications of urgent liver transplantation for acute flare up of hepatitis B in noncirrhotic liver were settled according to the model for end-stage liver disease (MELD) scores: once upon MELD scores ≥35 (criterion 1) or MELD score < 35 at beginning and increased in the subsequent 1 to 2 weeks (criterion 2). This study was to examine whether MELD score criteria for liver transplantation were valid in such an urgent condition. Eighty-three patients having acute flare up of hepatitis B virus with total bilirubin ≥17.5 mg/dL were included in this study. Among 83 patients, 20 patients met criterion 1. Five patients were transplanted and 15 patients died of liver failure with a median survival of 17 days. Fifty-one patients met criterion 2. Nineteen were transplanted, 30 patients died of liver failure with a median survival of 23.5 days, and 2 patients recovered from this critical condition. The other 12 patients did not meet criteria 1 and 2, and urgent liver transplantation was spared although 5 patients needed liver transplantation in subsequent 2 to 3 months. Therefore, the sensitivity of MELD score criteria for urgent liver transplantation was 100% and specificity was 85.7%. In conclusion, determination of urgent liver transplantation for hepatitis B with acute liver failure is crucial. MELD score criteria are valid to make a decision of urgent liver transplantation for hepatitis B patients with acute flare up and liver failure.