Pancreatic cancer (PC) is the fourth leading cause of death among all types of cancer. PC is very aggressive with a low 5-year overall survival rate. The highest prevalence of diabetes mellitus (DM), significantly exceeding the average population, is registered among patients with prostate cancer Recommendations for systemic screening of patients with diabetes for the detection of PC are not standardized. The purpose of this review is to present an analysis of current literature data on pathogenetic relationships between DM and PC and prospects for PC screening. Research data indicate that there is a bidirectional relationship between DM and PC, in which DM can act either as a risk factor for PC or as a marker of paraneoplastic syndrome of PC. In the differential diagnosis of type 2 diabetes, pancreatogenic diabetes and diabetes associated with PC, a set of clinical signs can be used. Patients with DM who have additional signs/symptoms of increased risk can be considered as a group subject to mandatory screening. Numerous studies of various proteomic, metabolomic, genetic and transcriptomic biomarkers PC have been published. The search for an easy-to-use clinically useful and cost-effective PC marker is still ongoing.