This large prospective study was conducted to assess short- and long-term mortality rates following the first diagnosis of myocardial infarction (MI) or diabetes during a 10-year period in Denmark. Among the 3,092,580 individuals of the study, a total of 77,147 cases of MI and 118,247 cases of new-onset diabetes were recorded. The data reported a ~2-fold elevated risk of cardiovascular death compared to the general population in both men and women with incident diabetes. This increased risk was noted immediately following initiation of glucose lowering medication (GLM) treatment and persisted after the first year. As for the rate ratio (RR) for cardiovascular death within the first year after MI, the risks were high in both men (RR=11.1, 95% CI: 10.8-11.5) and women (RR=14.8, 95% CI: 14.3-15.3). However, the RR quickly decreased in men (RR=2.11, 95% CI: 2.00-2.23) and women (RR=2.8, 95% CI: 2.64-2.97) after 1 year. Despite this substantial decline, these patients continued to carry a ~2- to 3-fold higher cardiovascular risk than the general population. Thus, these results emphasize the importance of an early and aggressive treatment in patients with diabetes as well as with a first-time MI to reduce the risk of future major cardiovascular outcomes.