Aims: Platelets are pivotal in arterial thrombosis, and platelet hyperresponsiveness may contribute to the increased incidence of cardiovascular events in diabetes mellitus. Consequently, we hypothesized that increased in vitro platelet aggregation responses exist in men with diabetes mellitus. Methods: The Danish Cardiovascular Screening Trial (DANCAVAS) is a communitybased cardiovascular screening trial including men aged 65-74 years. Platelet aggregation was tested using 96-well light transmission aggregometry with thrombin receptor-activating peptide (TRAP), adenosine diphosphate, collagen type-1, arachidonic acid, and proteaseactivated receptor-4 in three concentrations. Further, cardiovascular risk factors and coronary artery calcification (CAC), estimated by CT-scans and ankle-brachial index were obtained. Results: Included were 720 men aged 65-74 years, 110 with diabetes mellitus. Overall, there was no difference in platelet aggregation among men with versus without diabetes mellitus when adjusting for, or excluding platelet inhibitor treatment and men with established cardiovascular disease (CVD). This was true for all agonists, e.g. 10 µM TRAP-induced platelet aggregation of median 69 % (IQR 53-75) versus 70% (IQR 60-76) in men with versus without diabetes mellitus. Platelet aggregation did not correlate with HbA1c, or CAC. Men with diabetes mellitus displayed higher CAC, median 257 Agatston Units (IQR 74-1141) versus median 111 Agatston Units (IQR 6-420) in the remaining individuals, p<0.0001.