NASH is a clinico-pathological entity characterized by the development of histological changes of inflammation and fibrosis in the liver that are nearly identical to those induced by excessive alcohol intake, but in the absence of alcohol abuse. Nonalcoholic steatohepatitis occurs commonly children with additional comorbidities such as obesity and diabetes mellitus. Paralleling the increasing prevalence of obesity and type 2 diabetes in the pediatric population, nonalcoholic fatty liver disease (NAFLD) and especially its more severe histological form NASH, is expected to become one of the most common causes of end-stage liver disease in both children and young adults.