Myocardial infarction (MI) imposes a significant health burden to the Australian population. However, detailed economic implication of MI on the Australian healthcare system has not been exhaustively explored. To estimate the current chronic management cost and project the future healthcare cost burden of MI, from the Australian healthcare system perspective. A generalized linear model with a gamma outcome distribution and negative inverse link function was used to estimate the current chronic management cost burden of MI while a dynamic multistate Markov model constructed to project the future healthcare cost burden of MI over 20 years (2019-2038). For all projected costs, 5% annual discounting was applied in the base case, as per Australian guidelines. We identified all people, 59,260, aged ≥ 30 years discharged from a public or private hospital following MI between 2012 and 2017 from the Victorian Admitted Episode Dataset. We estimated annual chronic management cost of MI by age, sex, socioeconomic disadvantage and years of follow-up. We used these data to project the future healthcare cost burden of MI. Cost in Australian dollar (AUD). The current annual chronic management cost of MI was estimated to be AUD 14,412 (95% confidence interval: AUD 14,282, AUD 14,542) per person. This cost was higher among advanced age group, male participants, during first year of follow-up and people in the most socioeconomically disadvantaged quintile. The projected total healthcare cost following MI was AUD 85.1 billion (95% uncertainty interval AUD 80.8 billion, AUD 89.8 billion) from 2019 to 2038. Our projections suggest that MI will cost the Australian healthcare system over AUD 85 billion in the coming years. Cost estimates based on key sociodemographic characteristics and socioeconomic disadvantage are expected to inform future health economic modelling studies for MI prevention strategies and interventions.