Assessment of prognosis in fulminant hepatic failure (FHF) is essential for the need and appropriate timing of orthotopic liver transplantation (OLT). In this study we investigated the prognostic efficacy of King's College criteria, Clichy's criteria, Model for End-Stage Liver Disease (MELD), and Pediatric End-Stage Liver Disease (PELD) in 120 consecutive patients with FHF. Survival with medical therapy (18%), death without OLT (15%), and receipt of a liver transplant were similar in adults (n = 64) and children (n = 56). MELD scores were significantly higher in patients who died compared to those who survived without OLT, both in adults (38 +/- 7 vs. 26 +/- 7, P = 0.0003) and children (39 +/- 7 vs. 23 +/- 6, P = 0.0004). Using logistic regression analysis in this cohort of patients, concordance statistics were significantly higher for MELD (0.95) and PELD (0.99) when compared to King's College (0.74) and Clichy's criteria (0.68). When data was analyzed in a Cox model including patients receiving transplants and censoring the time from admission, the concordance statistic for MELD (0.77) and PELD (0.79) remained significantly higher than that of King's College criteria but not higher than that of Clichy's criteria. In conclusion, this study is the first to show that MELD and PELD are superior to King's College and Clichy's criteria to assess prognosis in FHF. However, because data was generated from a single center and included a rather low number of patients who survived or died without OLT, further confirmation of our findings is required.