Objectives: Gastroenteropancreatic neuroendocrine tumors (GEP-NET) are heterogeneous tumor groups, and they are rarely seen. Our study aims to analyze the clinicopathologic, demographic, and survival features of patients with GEP-NET. Methods: The data of 149 patients was collected retrospectively. Clinicopathologic, demographic, and survival features of patients with GEP-NET were investigated. Survival analysis was performed by using the Kaplan–Meier method and compared with the log-rank test. Univariate and multivariate analyses were performed to determine independent prognostic predictors of overall survival (OS). Results: Of 149 patients with GEP-NET, 65 patients (43.6%) were female and 84 patients (56.4%) were male. The most common, primary site of GEP-NET was stomach (40.3%). It was followed by pancreas (17.4%), small bowel/appendix (16.8%), colorectal (14%), and unknown primary (11.5%), respectively. The 3- and 5-year OS rate for the entire cohort were 69% and 60%, respectively. Median OS was not calculated, but the mean OS was 66.2 months. The factors significantly affecting the OS rate were age, grade, presence of metastasis at diagnosis, tumor diameter, and Ki-67 proliferation index in the univariate analysis. However, age was only meaningful in the multivariate analysis. Conclusion: Patients with GEP-NET under 50 age who have smaller tumor diameter, lower tumor grade, Ki-67 proliferation index, and absence of metastasis at the diagnosis have more prolonged survival.