The Model for End-Stage Liver Disease (MELD) scoring system has been established as a reliable measure of short-term mortality risk in patients with end-stage chronic liver disease. The aim of this study was to evaluate the prognostic value of the MELD scoring as a predictor of fulminant hepatic failure (FHF) and death in patients with acetaminophen poisoning. Prospectively, serial measurements of the 3 MELD components—INR, bilirubin, and creatinine—were performed in 460 patients with acetaminophen-induced liver injury. Starting on the first day after the day of overdose, MELD score was significantly higher in patients who eventually developed hepatic encephalopathy (HE) than in those who did not. HE developed in 63 of 142 patients with a MELD score above 18 at 48-72 hours after the overdose (positive predictive value 44%) compared with 2 of 182 patients with a MELD score of 18 or below (negative predictive value 99%). Among 124 patients with FHF, a threshold MELD score of 33 on the day after the onset of HE had sensitivity of 60%, specificity of 69%, positive predictive value of 65%, and negative predictive value of 63%. However, the discriminative power of MELD score was not superior to that of INR alone or of the King's College Hospital criteria. Conclusion: MELD score may be useful as a predictor of FHF in patients admitted with acetaminophen toxicity. However, as a predictor of death from FHF, MELD score did not provide more information than the King's College Hospital criteria or INR alone. (HEPATOLOGY 2007;45:789–796.)