This study aimed to identify the costs and resources used for diabetes mellitus (DM) and macrovascular complications in Turkiye. The "Cost of Illness" method and a bottom-up costing approach were used in this study. We used e-Nabiz to identify patients with DM and collected their data from 2016 to 2020. We also examined macrovascular complications such as acute coronary syndrome, unstable angina, coronary artery disease, cerebrovascular events, transient ischemic attacks, carotid artery syndrome, intracranial hemorrhage, diabetic foot, heart failure, atrial fibrillation, and peripheral vascular disease using relevant ICD codes. No sampling was done; costs were calculated based on the entire population. When calculating per patient costs, all outpatient/inpatient, medication, intervention, and laboratory/screening tests were considered. Between 2016 and 2020, the e-Nabiz database recorded 7,656,700 people diagnosed with diabetes, a prevalence of 10.4%. The total 2020 cost for treating diabetes was $4,526,212,569 (31,276,128,849 TL), with an average patient cost of $591.145. The health-care expense for 991,945 people diagnosed with major vascular complications due to diabetes was $1,013,004,565.0 (6,999,861,544.16 TL) in 2020, with a per patient average cost also of $591.145 (4048.81 TL). Breakdown of the total cost is 44% for healthcare, 34% for medication, 12% for insulin, 6% for oral antidiabetic drugs, and 1% for testing supplies. Women have a complication rate of 11.2%, while men have a higher rate of 20.8%. DM is both a significant disease burden and an important economic burden. The findings will be a guide the development of effective strategies and sound health policies.