ObjectivesGastorenteropancreatic neuroendocrine (GEP-NET) tumors are the second most common tumors of the gastrointestinal tract. We aimed to investigate the clinicopathological features and factors affecting the prognosis of patients with GEP-NET.MethodsClinicopathological features of 158 patients were evaluated, including tumor location, TNM stage and grade, pathological features, presence of lymph nodes and distant metastases at the time of diagnosis, maximum tumor diameter and treatment details. Also, follow-up information was analyzed to discover possible prognostic factors.ResultsThe most common primary site is pancreas (45.6%, n = 72). Most of the GEP-NETs were nonfunctional (93.6%, n = 148). Of the 158 patients, 94 (59.5%) were grade 1, 46 (29.1%) grade 2, and 18 (11.4%) grade 3. The 1-year, 3-year, and 5-year survival rates were 82.3% (130/158), 61.4% (70/114), and 47.2% (35/74), respectively. In multivariate analysis, histological grade (P = 0.04) and TNM stage (P < 0.001) were independent prognostic factors for survival in patients with GEP-NET.ConclusionsThey are increasing in frequency and are the most common tumors in the pancreas. Nonfunctional tumors made up the majority of cases. The main treatment was surgical resection. Histological grade and TNM stage are independent prognostic factors.