Population-based data on myocardial infarction rates in the Islamic Republic of Iran have not been reported on a national or provincial scale. In a cross-sectional study, data were collected on 20 750 new cases of myocardial infarction (ICD10 codes I21–22) admitted to hospitals and registered by the Iranian Myocardial Infarction Registry in 2012. The crude and age-adjusted incidence for the 31 provinces and the whole country were directly calculated per 100 000 people using the WHO standard population. Overall, males comprised 72.4% of cases and had a significantly lower mean age at incidence than women [59.6 (SD 13.3) years versus 65.4 (SD 12.6) years]. The malefemale incidence ratio was 2.63. The age-standardized myocardial infarction incidence rate was 73.3 per 100 000 in the whole country (95% CI 72.3%–74.3%) and varied significantly from 24.5 to 152.5 per 100 000 across the 31 provinces. The study provides baseline data for monitoring and managing cardiovascular diseases in the country.