|Autoimmune hepatitis (AIH) is caused by an immune disorder and chronic active hepatitis on liver histology. Associations between AIH and numerous immune mechanism disorders have been elucidated, but the precise mechanisms remain unknown.Specific serum markers of AIH remain to be established, and the diagnostic criteria for AIH have improved over time. Japanese guidelines for AIH were developed in 2013 based on the results of a nationwide survey conducted in 2009 and recent research findings. The latest nationwide survey of patients with AIH in 2015 aimed to elucidate the trends and characteristics of AIH in Japan, and to identify differences in AIH between acute hepatitis and chronic hepatitis.Health-related quality of life (HrQoL) in patients with AIH has remained unclear. We recently assessed the HrQoL in patients with AIH, chronic hepatitis C (CHC), and in healthy individuals using the Japanese version of the Chronic Liver Disease Questionnaire (CLDQ) and the 36-Item Short Form Survey (SF-36). The HrQoL was more impaired among patients with AIH than among healthy individuals, but the CLDQ and SF-36 were similar to those of patients with CHC. Having a background with cirrhosis, complications, and treatment were associated with HrQoL among patients with AIH.Here, we present the results of these two studies in Japan and comparisons of the clinical characteristics of AIH between Japan and other countries.