The major aim of this review was to ascertain whether effective evidence-based treatments for acute coronary syndromes (ACS) are underutilized in women in various geographic areas compared with men. The focus of our review was the relative use of effective treatments in patients with coronary angiographic evidence of obstructive coronary disease, defined as a lumen stenosis >50% of the adjacent non-diseased arterial diameter. We searched MEDLINE, and the Cochrane Database between January 1998 and May 2008. Only a few of the published clinical registries on ACS provide data on treatments dichotomized by confirmed coronary angiographic disease. Consequently, we also accessed individual patient-level data from 3 established ACS registries: the Finnish TACOS (Tampere Acute COronary Syndrome), the British EMMACE 2 (Evaluation of Methods and Management of Acute Coronary Events) and the Argentine PACS-ITALSIA (Prognosis in Acute Coronary Syndromes and the ITALian hospital Sindrome Isquemico Agudo). Despite presenting with higher risk characteristics and having higher in-hospital and 6 months risk of death, women with ACS and obstructive coronary artery disease were apparently treated less aggressively with secondary preventive drugs than were men, being less likely to receive aspirin, beta-blockers and statins at discharge. Overall, coronary revascularization appears to be performed in a similar proportion of women and men - once angiography has been performed and the coronary anatomy is known. However, substantial geographic variation exists in the relative rate of coronary angiography in men and women. In United Kingdom coronary revascularization tends to be done less frequently in women. Our study, therefore, demonstrates a gender bias in the delivery of secondary drug treatments for ACS, even for patients with documented significant coronary disease.