Aims and hypothesis: Detection of high glycated hemoglobin (A1c) is associated with worse postoperative outcomes, including predisposition to develop systemic and local infectious events. Diabetes and infectious Outcomes in Cardiac Surgery (DOCS) study is a retrospective case-control study aimed to assess in DM and non-DM cardiac surgery patients if a new screening and management model, consisting of systematic A1c evaluation followed by a specialized DM consult, could reduce perioperative infections and 30-days mortality. Methods: Effective July 2021, all patients admitted to the cardiac surgery of IRCCS ISMETT were tested for A1c. According to the new protocol, glucose values of patients with A1c ≥6% or with known diabetes were monitored. The diabetes team was activated to manage therapy daily until discharge or provide indications for the diagnostic-therapeutic process. Propensity score was used to match 573 patients managed according to the new protocol (the Screen+Group) to 573 patients admitted before July 2021 and subjected to the traditional management (Screen-). Results: Perioperative prevalence of infections from any cause, including surgical wound infections (SWI), was significantly lower in the Screen+ as compared with the Screen- matched patients (66 (11%) vs 103 (18%) p=0.003). No significant difference was observed in 30-day mortality. A1c analysis identified undiagnosed DM in 12% of patients without known metabolic conditions. Conclusions and interpretation: In a population of patients undergoing cardiac surgery, systematic A1c evaluation at admission followed by specialist DM management reduces perioperative infectious complications, including SWI. Furthermore, A1c screening for patients undergoing cardiac surgery unmasks unknown DM and enhances risk stratification.