Objective: To examine whether there are sex differences in the characteristics, management, and clinical outcomes of patients with an ST-elevation myocardial infarction (STEMI). Design, setting: Cohort study; analysis of data collected prospectively by the CONCORDANCE acute coronary syndrome registry from 41 Australian hospitals between February 2009 and May 2016. Participants: 2898 patients (2183 men, 715 women) with STEMI. Main outcome measures: Rates of revascularisation (percutaneous coronary intervention [PCI], thrombolysis, coronary artery bypass grafting [CABG]), adjusted for GRACE risk score quartile. Secondary outcomes: timely vascularisation rates; major adverse cardiac event rates; clinical outcomes and preventive treatments at discharge. Results: The mean age of women with STEMI at presentation was 66.6 years (SD, 14.5 years), of men, 60.5 years (SD, 12.5 years). The proportions of women with hypertension, diabetes, prior stroke, chronic kidney disease, chronic heart failure, or dementia were larger than those of men; fewer women had histories of previous coronary artery disease or myocardial infarction, or of prior PCI or CABG. Women were less likely to have undergone coronary angiography (odds ratio, adjusted for GRACE score quartile [aOR], 0.53; 95% CI, 0.41−0.69) or revascularisation (aOR, 0.42; 95% CI, 0.34−0.52); they were less likely to have received timely revascularisation (aOR, 0.72; 95% CI, 0.63−0.83) or primary PCI (aOR, 0.76; 95% CI, 0.61−0.95). Six months after admission, the rates of major adverse cardiovascular events (aOR, 2.68; 95% CI, 1.76−4.09) and mortality (aOR, 2.17; 95% CI, 1.24−3.80) were higher for women. At discharge, significantly fewer women than men received β-blockers, statins, and referrals to cardiac rehabilitation. Conclusion: Women with STEMI are less likely to receive invasive management, revascularisation, or preventive medication at discharge. The reasons for these persistent differences in care require investigation.