Aim Autoimmune hepatitis (AIH) commonly shows bimodal distribution of onset age: at young adulthood and at 50–60 years‐of‐age. However, in recent times, the incidence of elderly‐onset AIH seems to be increasing. This study aimed to investigate whether the incidence of elderly‐onset AIH is increasing, and whether these patients show any clinical features different from those observed in younger patients. Methods Data about patients with newly diagnosed AIH visiting the Japanese Red Cross Society Himeji Hospital, Himeji, Hyogo, Japan, were retrospectively collected for the period ranging from January 2010 to May 2016. A total of 71 patients (56 women and 15 men, age 18–88 years) were included in this study. Patients were divided into two cohorts: elderly (≥70 years; n = 28) and adult cohort (15–69 years; n = 43). Demographic and clinical characteristics, biochemical and serological markers, radiological and histological findings, and therapeutic courses were evaluated. Results The median age of the patients was 65 years, the most frequent range being the 70s (37%), followed by the 60s (25%). The elderly cohort had significantly higher levels of serum immunoglobulin G and antinuclear antibody, lesser hepatitis activity scores, and lesser chance of developing other autoimmune diseases. They tended to have higher C‐reactive protein levels and lower serum alanine aminotransferase levels. All patients achieved clinical remission after treatment. Conclusions This study clearly showed an increase in the incidence of elderly‐onset AIH. These patients had some unique characteristics, showing that the development of elderly‐onset AIH is influenced by age‐associated immune dysfunction called immunosenescence.