Myocardial infarction (MI) is highly detrimental and healthcare intensive with a high incidence globally. This study aimed to estimate the individual healthcare costs of MI in Denmark from a public health provider perspective. In this nation-wide registry-based cohort study, individuals with incident MI between 2012 and 2016 were propensity score-matched 1:3 with non-MI controls. Excess costs were calculated as costs of patients with MI minus average costs of matched controls, accounting for all individual-level hospital contacts and treatment, primary care, and reimbursed prescription medicine, analyzed as acute or long-term costs in 6-month intervals during 4 years before and 4 years after the MI event. For acute costs and the first 6 months, data were available to extend the cohort period to include index year 2019. In total, 34 310 individuals with a first-time MI were matched to non-MI controls. The mean total acute healthcare cost of first-time MI was €11 462 (95% confidence interval: 11 313-11 612), and cost was €5966 (5788-6145) during the first 6 months, decreasing to €1696 (1565-1827) during the next 6 months. Females with MI incurred 26% lower acute costs and 20% lower excess costs during the first 6 months than males did but higher excess costs than males past 1 year. Costs were highest in people aged 60 to 79 and gradually decreased over the later study years. We found that MI is associated with significant acute and long-term health care costs. With constant or slightly decreasing healthcare expenses on a background of a general decline in MI incidence rates, the total healthcare spendings on MI may decline in the years ahead.