Simple SummaryGastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs) are the most common neuroendocrine tumors, with the ability of overexpressing somatostatin receptors (SSTRs) on the cells’ surface. The prevalence and the incidence of GEP-NENs have been constantly increasing over the last years, reflecting the improved sensitivity of imaging modalities and effectiveness of new therapeutic options. The theragnostic approach, which is able to combine diagnosis and therapy, is widely applied in GEP-NENs patients through the administration of radiolabeled SSTR analogs. In the era of personalized medicine, this combined approach represents an opportunity to plan a real tailored treatment in patients with GEP-NENs.AbstractGastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs) constitute an ideal target for radiolabeled somatostatin analogs. The theragnostic approach is able to combine diagnosis and therapy by the identification of a molecular target that can be diagnosed and treated with the same radiolabeled compound. During the last years, advances in functional imaging with the introduction of somatostatin analogs and peptide receptor radionuclide therapy, have improved the diagnosis and treatment of GEP-NENs. Moreover, PET/CT imaging with18F-FDG represents a complementary tool for prognostic evaluation of patients with GEP-NENs. In the field of personalized medicine, the theragnostic approach has emerged as a promising tool in diagnosis and management of patients with GEP-NENs. The aim of this review is to summarize the current evidence on diagnosis and management of patients with GEP-NENs, focusing on the theragnostic approach.