Acute liver failure (ALF) is a very rare but devastating illness in children. Specific treatment to recovery is often not available, and the underlying cause of the liver failure is often unknown and diverse especially in children. Liver transplantation has increased the chance of survival; however it needs an optimal timing to reach the best result which is not familiar to pediatrician. This article discusses the current knowledge of the epidemiology, backgrounds and factors to be considered before establishing the treatment of ALF in children.