We experienced two cases of pediatric nonalcoholic steatohepatitis (NASH) associated with hypopituitarism. The first patient was diagnosed with a craniopharyngioma at 5 years of age. After an operation to treat the condition, the patient gradually became obese, and an elevation of transaminases was observed. At 16 years of age, the patient was diagnosed as having NASH with liver cirrhosis. He was started on hormone replacement therapy; however, his insulin resistance and liver fibrosis, as evaluated by hyaluronic acid and platelet count, progressed. In addition, his hyperleptinemia continued. The second patient was diagnosed, at 10 years of age, as having pituitary dysfunction due to fetal asphyxia, and he was started on hormone replacement therapy. This patient was noted to have been obese throughout his life. He was diagnosed as having NASH with advanced fibrosis at 18 years of age. It is important for both hepatologists and endocrinologists to be aware of the association between pituitary dysfunction and NASH.