Background: Gastroenteropancreatic neuroendocrine tumors, aheterogeneous group of neoplasms, originates from the neuroendocrinesystem of the gastrointestinal tract and pancreas. There are limitednumber of studies investigating neuroendocrine tumors in Turkey.Aims: To define the clinicopathologic, demographic, and survivalfeatures of patients with gastroenteropancreatic neuroendocrinetumors.Study Design: A retrospective observational cohort study.Methods: We reviewed hospital records of patients and data wasanalyzed retrospectively. We investigated the clinical, pathological,survival features, and prognosis of patients with gastroenteropancreaticneuroendocrine tumors (n=128) admitted to the medical oncologydepartment between year 2003 and 2014. Survival estimation wasperformed by the Kaplan-Meier method. Univariate and multivariateCox regression models were utilized to investigate the prognosticfactors for survival.Results: Of 128 patients with gastroenteropancreatic neuroendocrinetumors, 61 (47.7%) were female and 67 (52.3%) were male. Themost common site of the tumor was stomach (36.7%), while themost common stage of tumor at diagnosis was stage 4 (40.9%). Themedian follow-up period was 37 months, while the 3- and 5-yearoverall survival rates were 78% and 69%, respectively. The factorssignificantly affecting overall survival rate were clinical stage, grade,presence of metastasis at diagnosis, and Ki-67 proliferation index.These factors were associated with the 3- and 5-year overall survivalrate. Moreover, grade (hazard ratio: 8.34, 95% confidence interval:2.16-32.22, p=0.01) and presence of metastasis at diagnosis (hazardratio: 3.18, 95% confidence interval: 1.30-7.77, p=0.01) independentlypredicted overall survival in multivariate model following adjustmentfor age and gender.Conclusion: Higher-grade and presence of metastasis at diagnosis arenegative independent prognostic indicators of survival in patients withgastroenteropancreatic neuroendocrine tumors.