Type 1 diabetes is usually associated with other autoimmune diseases. Parietal cell antibodies (PCA) are found in 20% of type 1 diabetic patients which might be an early sign of autoimmune gastritis and pernicious anemia. PCA destroy the gastric H+/K+ ATP-ase. The chronic auto-destruction of the proton pump leads to hypo/achlorhydria and hypergastrinemia which leads to the hyper/dysplasia of enterochromaffin-like cells (ECL). ECL hyper/dysplasia is known to increase the likelihood of gastric carcinoid tumor development in affected patients. Gastric carcinoid tumors forming from the hyperplasia of ECL cells are found in 4-9% of patients having autoimmune gastritis or pernicious anemia. The 29-years-old type 1 diabetic patient, having primer hyperthyroidism was admitted to our clinic because of gastric pain. Results of endoscopy and biopsy showed multiple small polyps in the fundus with non-antral hypergastrinemic (type A) atrophic gastritis. The parietal cell antibody test was positive, the serum chromogranin A level was 289,7 ng/ml (normal value $ 98 ng/ml), TSH level was 9,93 mIU/L. The histological examination indicated carcinoid tumor. Sandostatin therapy was started then partial gastrectomy was done. After the operation the plasma chromogranin level normalized. Non-antral, multiple polyps could cover silent neuroendocrine tumors, which are slowly growing benign endocrine tumors, however, they also might be high malignity endocrine carcinomas. These tumors could be easily recognized in the clinical practice by measuring the serum or tissue chromogranin A level and other markers of tumor growth. Thus screening of gastric endocrine tumors in type 1 diabetic patients with co-morbid autoimmune diseases is recommended.