Neuroendocrine tumors represent a group of neoplasias characterized by significant histopathologic and biological heterogeneity. Diagnosis of neuroendocrine tumors relies upon histological examination augmented by newer techniques such as position emission tomography, meta-iodobenzylguanidine scintigraphy or octreoscan. Surgery represents the definite and curative therapeutic approach in early phase tumors. In metastatic or advanced disease, medical treatment is the best choice. Somatostatin analogs allow adequate control of the carcinoid syndrome, without a significant effect on tumor cell growth. Interferon-alpha may represent an alternative, alone or in association with somatostatin analogs. Chemotherapy is the best choice in the treatment of neuroendocrine tumors characterized by a poor differentiation grade and a high proliferation rate.