Abstract: Objective To explore the clinical features and pathogenesis of pancreatic cancer concomitant with diabetes. Methods 34 cases of pancreatic cancer in the past 5 years were searched by case management computer system. Results Of these 34 cases, 15 cases were pancreatic cancers concomitant with diabetes mellitus,of which there were 9 men and 6 women, the morbidity rate was 44.1%. 5 cases (33.3 96 ) suffered from diabetes before pancreatic cancer diagnosed,whilc the other 10 cases (66.7 % ) of diabetic patients were diagnosed with cancer simultaneously.Conclusion Diabetes occur more frequently in patients with pancreatic cancer than in the general population. Diabetes in patients with pancreatic cancer is presumably caused by the tumor.