Introduction: Autoimmune hepatitis (AIH) is a rare liver disease with a favorable prognosis following immunosuppression. In this work-up, we present our long-term experience with this patient collective. Patients and Methods: Overall, we were able to retrospectively evaluate data from 535 patients with histologically confirmed AIH over a period of 18 years between 2002 and 2020. Results: As expected, almost ¾ of the patients were women (74.5 %) of middle age (47.0 ± 14.9 years). Type I AIH was diagnosed in almost all patients (97.5 %). However, 88 patients (16.4 %) revealed an overlap to primary biliary cholangitis (PBC). In contrast, overlap to primary sclerosing cholangitis (PSC) was detected in only 22 patients (3.7 %). Regarding auto-antibody profile, positivity for anti-nuclear antibodies (ANA) was found in 388 patients (72.5 %); smooth-muscle actin (SMA)-titer was positive in 90 patients (16.8 %), anti-mitochondrial antibodies (AMA) were detected in 43 individuals (8.0 %), and we found positive p-anti-neutrophil cytoplasmic antibodies (p-ANCA) in 12 patients (2.2 %). More than ¾ of the patients (n = 417 ≈ 77.9 %) were initially treated with corticosteroids (1 mg/kg/day) and this therapy was continued in almost all subjects (97.4 %) in low dose (5 - 7.5 mg/day) as maintenance therapy. Steroid-saving and remission-maintaining therapy with azathioprine was carried out in 380 patients (71.0 %). Mycophenolate mofetil (MMF) or calcineurin-inhibitors (CNI) were used as second- or third-line immunosuppression. Acute liver failure (ALF) - as the first manifestation of AIH - was diagnosed in 101 patients (18.8 %). Hepatocellular carcinoma (HCC) was detected in at least 6 patients (1.1 %). Liver transplantation (LT) was performed in 51 patients (9.5 %) who progressed to cirrhosis despite immunosuppression. Unfortunately, a total of 45 patients (8.4 %) died of cirrhosis-related complications (infected ascites, bleeding, encephalopathy) without chance for adequate organ offer.Conclusion: We here present our long-term experience with a significant number of patients diagnosed with AIH over a long observation period of 18 years. In general, patients with AIH can adequately be managed with good clinical outcome at a liver center requiring immunosuppressive therapy. However, HCC-screening, acute-on-chronic (AOC) liver decompensation, or liver transplantation have to be taken into consideration carefully.