AIM: Pancreatic cancer is the 11th most common cancer in the world. The importance of early diagnosis and treatment for curative treatment is very high. Many studies have shown a relationship between diabetes mellitus (DM), smoking, genetic factors, obesity, nutritional habits and sedentary life and pancreatic ductal adenocarcinoma (PDAC). In this study, we aimed to investigate the relationship between DM onset age and PDAC. MATERIALS AND METHODS: 158 patients with PDAC and DM were compared with 244 patients with DM in the control group. We retrospectively analyzed PDAC risk factors with a focus on DM onset age. RESULTS: It was calculated that the risk of PDAC increased 8.5 times in patients diagnosed with DM after 60 years of age compared to those diagnosed with DM before 60 years of age (HR = 8.54, 95% CI 5.66-12.90, p<0.0001). The interval between the diagnosis of DM and the diagnosis of PDAC peaked at 32 months (95% CI 27.90-35.56). When the age of DM onset was evaluated, it was observed that peaks were around 50 years in the group without PDAC and 60 years in the group with PDAC. CONCLUSION: In patients with DM onset after the age of 60, we recommend keeping in mind the increased risk of PDAC and evaluating these patients for PDAC, even if they are asymptomatic.