Autoimmune hepatitis (HAI) is a rare chronic inflammatory disease of the liver in children. A simplified diagnostic score was proposed by the International Auto-immune Hepatitis Group (IAIHG) in 2008. The diagnosis of HAI is based on clinical, immunological and histological criteria. Liver biopsy (LP) is an essential examination for the diagnosis of HAI. Histological criteria help confirm the diagnosis and guide treatment. The presence of interface hepatitis and plasma cells within this infiltrate are important diagnostic features, but are not specific. PBF can also be used to assess the presence of fibrosis, which is quantified using the METAVIR score. The IAIHG score helps clinicians make the diagnosis. Use of the HAI 2008 simplified diagnostic score could contribute to early diagnosis, particularly in forms of chronic hepatitis. Despite moderate specificity, it is preferable to over-diagnose while awaiting review, and prescribe corticosteroid therapy, rather than let the child progress to liver cirrhosis.