Gastric neuroendocrine tumors (NET ventriculi) are rare neoplasms of the gastrointestinal tract, increasing in incidence over last fifty years, what partly could be explained by the common use of upper gastrointestinal tract endoscopy. Pathogenesis of the NET ventriculi is not fully understood, however it is well known, that in all NET ventriculi types there is a hyperplasia of enterochromaffine-like cells (ECL) related to different stimuli. NET ventriculi type 1 is related to autoimmunological atrophic gastritis and hypergastrinaemia, NET ventriculi type 2 with hypergastrinemia in the course of Zollinger-Ellison syndrome associated with multiple endocrine neoplasia (MEN 1) syndrome, NET ventriculi type 3 are sporadic tumors not related to hypergastrinaemia, usually with poor prognosis. Localization of tumors and possible metastases, histo-pathological confirmation of the neoplasm type and defining the source of hypergastrinaemia is essential in diagnostic of NET ventriculi. Treatment dependent on the NET ventriculi type is based on endoscopic or surgical tumor excision in type 1 and 2 and surgical radical treatment in type 3. There is an increased interest in the use of somatostatin analogues (SSA) both in type 1 and in cases with dissemination of the disease. Advances in understanding of the pathogenesis and recent development of medical techniques leads to the improvement of diagnostic and therapy in these group of neoplasms.