Abstract Background The incidence of pancreatic neuroendocrine neoplasms (pNEN) is increasing. This study aimed to evaluate predictors of overall survival and the indication for surgery. Methods Data collected between October 2001 and December 2012 were analysed. Histological grading and staging was based on the classifications of the World Health Organization, the International Union Against Cancer and the European Neuroendocrine Tumour Society. Results Some 310 patients (150 female, 48·4 per cent) underwent surgical resection. The final survival analysis included 291 patients. Five-year overall survival differed according to tumour grade (G): 91·0 per cent among 156 patients with pancreatic neuroendocrine tumours (pNET) G1, 70·8 per cent in 111 patients with pNET G2, and 20 per cent in 24 patients with pancreatic neuroendocrine carcinomas (pNEC) G3 (P < 0·001). Tumours graded G3 (hazard ratio (HR) 6·96, 95 per cent confidence interval 3·67 to 13·21), the presence of distant metastasis (HR 2·41, 1·32 to 4·42) and lymph node metastasis (HR 2·10, 1·07 to 4·16) were independent predictors of worse survival (P < 0·001, P = 0·004 and P = 0·032 respectively). Eight of 61 asymptomatic patients with pNEN smaller than 2 cm had tumours graded G2 or G3, and six of 51 patients had lymph node metastasis. Among patients with pNEC G3, the presence of distant metastasis had a significant impact on the 5-year overall survival rate: 0 per cent versus 43 per cent in those without distant metastasis (P = 0·036). Conclusion Neuroendocrine tumours graded G3, lymph node and distant metastasis are independent predictors of worse overall survival in patients with pNEN.