Previous studies have suggested that obesity is associated with an increased risk of developing pancreatic cancer. However, it is unclear whether the association between body mass index (BMI) and the risk of pancreatic cancer differs by glycemic status.This study investigated how the association between BMI and pancreatic cancer differs by glycemic status.This Nationwide cohort study included 9,520,629 adults who underwent the Korean National Health Screening in 2009 and were followed until 2018. BMI was divided into underweight (BMI, <18.5 mg/dL), normal (BMI, 18.5-22.9 mg/dL), overweight (BMI, 23-24.9 mg/dL), obesity stage I (BMI, 25-29.9 mg/dL), and obesity stage II (BMI, ≥35 mg/dL). Multivariable Cox proportional hazard models were used to estimate Hazard Ratios (HRs) and 95% confidence intervals (CIs) after adjusting for potential confounders.During the 78.4 million person-years of follow-up, 15,245 people were newly diagnosed with pancreatic cancer. In the normoglycemia group and impaired fasting glucose (IFG) group, even being overweight was associated with an increased risk of pancreatic cancer; HR 1.11, 95% CI 1.05-1.18, and HR 1.15, 95% CI 1.16-1.24, respectively. In both groups, the risk of pancreatic cancer was the highest in obesity stage II; HR 1.25, 95% CI 1.08-1.44 and HR 1.31, 95% CI 1.12-1.53, respectively. Among individuals with diabetes, the risk of pancreatic cancer was highest in those who were underweight, although the difference was not statistically significant; HR, 1.15, 95% CI 0.89-1.49.This study found that being overweight, as well as obese, increases pancreatic cancer risk in people with normoglycemia or impaired fasting glucose. In contrast, among people with diabetes, being underweight was linked to the highest cancer risk. These contrasting associations suggest different underlying mechanisms: metabolic factors tied to excess weight may drive cancer in normoglycemic or prediabetic individuals, while unintended weight loss in diabetes could indicate early or existing cancer.Our findings highlight the need for individualized risk assessment and surveillance, rather than a one-size-fits-all screening approach, to improve pancreatic cancer prevention and early diagnosis efforts.