Abstract Background Large randomized clinical trials have shown that sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce the risk of adverse kidney and cardiovascular outcomes in patients with heart failure, chronic kidney disease, or type 2 diabetes mellitus (T2DM) at high risk of atherosclerotic cardiovascular disease. Whether these effects might differ between individual SGLT2-inhbitors remain unclear given the lack of head-to-head comparisons. Purpose To examine the association between treatment with dapagliflozin versus empagliflozin and the long-term rate of major adverse cardiovascular events (MACE) in patients with T2DM. Methods Using nationwide registries, all Danish residents with T2DM, who initiated treatment with dapagliflozin or empagliflozin from 2015 to 2020, were identified. Only treatment with dapagliflozin or empagliflozin was considered in the present analysis, since approximately 3% initiated treatment with other SGLT2-inhibitors (i.e., canagliflozin and ertugliflozin). Patients were followed from date of the first claimed prescription of dapagliflozin or empagliflozin until the outcome of interest, emigration, death, or end of study (December 31, 2021). The primary outcome was a composite endpoint of major adverse cardiovascular events (i.e., time to first heart failure hospitalisation, acute myocardial infarction (AMI), stroke, or all-cause mortality). The primary outcome was compared between the dapagliflozin and empagliflozin group, overall and in prespecified subgroups of interest, with multivariable Cox proportional hazards regression models. Results In total, 61,031 patients with T2DM initiated treatment with dapagliflozin (N=21,028; 34.5%) or empagliflozin (N=40,003; 65.5%). The median age of study population was 62.6 years (25th-75th percentile, 54.2-70.8 years), and 62.6% were men. There were no clinically significant differences between the dapagliflozin and empagliflozin group with respect to age, sex, and clinical characteristics. The median follow-up was 3.1 years (25th-75th percentile, 1.9-4.5 years). The adjusted long-term hazard ratios of the primary outcome, overall and in prespecified subgroups of interest, are displayed in the Figure. Compared with empagliflozin, treatment with dapagliflozin was not associated with a significantly different rate of the primary outcome (HR 1.02 [95% CI, 0.97-1.07]). The observed association was consistent across clinically relevant subgroups, including in patients with and without heart failure, chronic kidney disease, and atherosclerotic cardiovascular disease. Conclusion In a large, nationwide cohort of patients with T2DM, treatment with dapagliflozin was associated with a similar rate of major adverse cardiovascular outcomes compared with empagliflozin, and this association was consistent across clinically relevant subgroups. These findings suggest that the benefits of SGLT2-inhibitors can be characterized as a class-effect.