The neuroendocrine tumors of the stomach and duodenum constitute only minority of neoplasms in this localisation. However due to their clinical behaviour and/or hormonal syndromes they pose diagnostic and therapeutic challenge. They display distinct phenotypes, regarding their pathogenesis, pathology and clinical course. Herein we present Polish guidelines for biochemical, pathological and localisation diagnosis, and discuss therapeutic approaches, considering endoscopic and surgical treatment, pharmacological and radionuclide therapy.