Objective: Because patients with new-onset diabetes mellitus (DM) have a significantly increased likelihood of association with pancreatic cancer, we need to select the subgroup of diabetic patients who have more chance of association with pancreatic cancer. Methods: We retrospectively reviewed medical records of case group (151 patients with pancreatic cancer with new-onset DM) and control group (302 patients with new-onset DM without cancer). Results: Compared with the control group, pancreatic cancer group were older, had more weight loss, lower usual body mass index (BMI), more family history of pancreatic cancer (3.3% vs. 0.7%; P=0.044), and had less family history of DM (13.9% vs. 37.4%; P<0.001). If a new-onset DM patient did not have family history of DM, he was of age older than or equal to 65 years or had weight loss of >2 kg or had premorbid usual BMI <25 kg/m(2), pancreatic cancer associated DM could be discriminated from new-onset type 2 DM with 80.8% sensitivity, 67.6% specificity, 2.5% and 99.7% of positive and negative predictability for pancreatic cancer, respectively. Conclusions: Among patients who meet criteria for diabetes within 2 years, those who are elderly, have lower premorbid BMI, weight loss, no family history of DM, need screening of pancreatic cancer.