BACKGROUND: Liver transplantation is considered as the most powerful modality for patients with acute on chronic liver failure and fulminant hepatic failure. The aim of this study is to identify potential prognostic factors that may affect survival after emergent liver transplantation. METHODS: A total of 42 patients who underwent emergent liver transplantation at Gachon University Gil Medical Center from June 2005 to May 2013 were enrolled. The clinical scoring system analyzed for this study were as follows: Child-Turcotte-Pugh (CTP), model for end-stage liver disease (MELD), Model for end-stage liver disease with incorporation of serum sodium (MELD-Na), Acute physiology and chronic health evaluation II (APACHE II), and Sequential Organ Failure Assessment (SOFA). RESULTS: Preoperative SOFA and APACHE scores were closely related with patient's survival after the operation. Also, the changed value of SOFA while patients waited for their transplantation showed to be significant. In a univariate analysis, serum bilirubin and Glasgow Coma Scale (GCS) showed statistical significance for patient's prognosis. Several factors, such as the use of mechanical ventilator and inotropic agent for treating multiple organ failure were also important. The central nervous system and cardiovascular scores showed an intimate relation with the survival group by a more detailed analysis in SOFA. In a multivariate analysis, SOFA and bilirubin levels affected patient's survival. CONCLUSIONS: In emergent liver transplantation with acute on chronic liver failure and fulminant liver failure, recipient's hepatic function is an important factor along with the donated liver condition l eading to successful operation. Also, it is important to pay attention to the progression of organ failure in predicting the prognosis.