Background: Death from acute coronary syndrome (ACS) is avoidable with early reperfusion therapy, however, evidence suggests inequity in women's ACS treatment within a number of international healthcare systems, when compared to men's. Research indicates mortality rates are higher in some age groups of women when compared to men for the sub-group of ACS known as ST-segment elevation myocardial infarction (STEMI). Objective: To determine whether patient sex was associated with patterns of reperfusion treatment variation or increased inhospital mortality in patients with STEMI. Methods: We undertook retrospective analyses on a government database for patients admitted to Victorian public hospitals with STEMI. Patients were categorised into two age groups: 18-64 and 65-84 years (inclusive), to determine whether patient sex and these age groups influenced treatment from 2005 to 2008 and mortality from 2005 to 2010. Results: Both younger and older women received less frequent angioplasty with stent and more often received no reperfusion treatment than men in corresponding younger and older age groups (p = 0.006 and p < 0.001, respectively). Overall, women in both age groups were more likely to die inhospital than men from equivalent age groups with STEMI (p < 0.001, both groups). Conclusions: Proportionately, both younger and older women received less interventional reperfusion therapy for STEMI than their male cohorts, and died more often during admission than men. Further research needs to be undertaken to verify the findings and causes, and guide future research to ensure application of evidence to treatment in patients with STEMI.