The role of diabetes in intraductal papillary mucinous neoplasms (IPMNs) is not known. We investigated the prevalence of diabetes among patients with resected IPMNs and the association between diabetes, clinical and morphological features, and high-grade dysplasia or invasive cancer.We collected clinical, pathology, laboratory, and demographic data from 134 patients who underwent pancreatic resection for IPMN from a referral center in Germany. We identified 50 patients with diabetes (37%).Higher proportions of patients with diabetes were male and older, but did not have increased body mass index, compared to patients without diabetes. Diabetes was significantly associated with main-duct involvement (odds ratio [OR], 2.827; 95% CI, 1.059-7.546; P=.038) and high-grade dysplasia or invasive carcinoma (OR, 2.692; 95% CI, 1.283-5.651; P=.009). Risk of high-grade dysplasia or invasive cancer was even higher in patients with new-onset or worsening diabetes (OR, 4.615; 95% CI, 1.423-14.698; P=.011). Fifty-eight percent of patients (18/31) with weight loss at diagnosis had diabetes vs 32% of patients (31/97) without weight loss (P=.009). However, when the analysis was restricted to IPMNs with low-grade dysplasia, weight loss and diabetes were no longer associated (42% [5/12] vs 21% [9/44]; P=.133).In patients with IPMNs, diabetes is associated with increased risk of main duct involvement and high-grade dysplasia or invasive carcinoma. Studies are needed to determine the relationship between diabetes and progression of IPMNs, which might lead to strategies for early detection and prevention of invasive cancer. Findings from this study should be considered in the guidelines for management of IPMN.