OBJECTIVE To investigate the clinical features of autoimmune pancreatitis (AIP) with diabetes as the first manifestation, improve our understanding of the disease and highlight the recognition of special types of diabetes. METHODS A retrospective analysis was performed on 2 AIP patients diagnosed with diabetes at the First Affiliated Hospital of Anhui Medical University. RESULTS Two elderly patients with new-onset diabetes mellitus were admitted to the hospital with weight loss and yellowing of the skin. Imaging showed pancreatic enlargement, bile duct dilatation, and cholestasis. Auxiliary examination followed by histopathology or experimental hormone therapy revealed elevated IgG4 levels, and the patients were eventually diagnosed with AIP. CONCLUSIONS For elderly diabetic patients with atypical clinical characteristics, such as unexplained gastrointestinal symptoms or weight loss, IgG4 levels should be examined to rule out diabetes secondary to AIP.