The history of a 45-year-old male type 1 diabetic patient is presented. At the age of 29 years, he was diagnosed to have an autoimmune hepatitis with incipient liver cirrhosis. Five years later, a successful liver/pancreas transplantation was performed. Eighteen months later, however, pancreatic insufficiency occurred due to thrombosis of the pancreatic graft. Besides these conditions, iron deficiency, pernicious anemia, and autoimmune gastritis were also diagnosed. Serum parietal cell antibodies (PCA) and intrinsic factor antibodies (AIF) were positive. At 45, this patient was found to have a gastric carcinoid tumor. The clinical importance of PCA is discussed with regard to chronic atrophic gastritis and pernicious anemia, which both predispose toward gastric carcinoid tumors. Autoimmune type 1 diabetic patients who have a high prevalence of PCA should be screened for gastric autoimmune manifestations and tumors, as the history of this patient illustrates.