The aim of this study was to estimate the impact of sex on relative survival and excess mortality following acute myocardial infarction (AMI) using a population-based cohort within a relative survival framework. Patient-level data concerning demographics, co-morbidity, cardiovascular risk factors and treatments at discharge were extracted from the Swedish Web-system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies (SWEDEHEART), a population-based registry of outcomes for patients hospitalized with acute coronary syndrome. Patients were followed-up for their vital status after AMI hospitalisation, with censoring at the end of follow-up on the 31st of December, 2013.