Aims Primary malignant tumors of the small bowel constitute only about 1 – 2% of all gastrointestinal neoplasms. Although neuroendocrine tumors (NETs) are relatively rare, they still represent the second most common malignancy of the small bowel (after adenocarcinoma). Clinical manifestations include abdominal pain, bowel obstruction, diarrhea, weight loss and bleeding. The differential diagnosis of obscure gastrointestinal bleeding can sometimes be challenging for endoscopic as well as for radiological methods. The aim of the lecture is to present the diagnostic and therapeutic management of a patient with NET of the small bowel. Methods A literature research (in MEDLINE, PubMed and Google Scholar databases) was done focusing on diagnostics, endoscopic and surgical treatment of neuroendocrine tumor of the small bowel. Results We present a case of an 80-year-old man suffering from severe hypochromic anemia. Routine endoscopic methods did not show any any pathology explaining the severe anemia. Finally, a single ulcerative infiltration of the ileum was diagnosed by capsule endoscopy (CE). CT enterography did not reveal any other lesions. In accordance with a positive chromogranin A, endoscopic and radiological methods, a suspicion of NET was expressed. During the surgery 7 lesions were found and a resection of 120 cm of ileum was performed. The histology confirmed a diagnosis of NET grade 1, with a total number of 15 NET lesions in the specimen. Conclusions NETs located in the duodenum up to 1 cm in size can be treated endoscopically and are mostly isolated lesions. On the other hand, surgical treatment is recommended for NETs in the jejunoileum. They have a greater propensity to metastasize and NETs in this localization can even form more lesions. We present a patient with 15 NET lesions in the ileum diagnosed by CE and successfully treated by surgical resection of the ileum.