Aim: We aimed to determine the effect of diabetes mellitus (DM) on survival in pancreatic cancer and effects of pancreatic cancer on glycemic control in DM. Materials & methods: Patients with pancreatic cancer from 2007 to 2015, with and without DM, were matched 1:1. We compared characteristics between the groups and assessed 2-year survival with Kaplan–Meier analysis. Results: In patients with DM, hemoglobin A_1c decreased significantly over time (p = 0.01). In survival analysis, 2-year overall survival estimates were 15% (95% CI: 8–24%) for DM patients versus 26% (95% CI: 17–36%) for non-DM patients (p = 0.55). The hazard ratio for matched pairs was 1.15 (95% CI: 0.75–1.77; p = 0.51). Conclusion: DM did not decrease survival in pancreatic cancer. Pancreatic cancer did not affect glycemic control.