More women than men die of coronary artery disease (CAD) each year. In women, cardiovascular disease can present atypically and may be caused by small vessel disease rather than by major epicardial coronary luminal narrowing. Women with CAD tend to have more diffuse disease, endothelial dysfunction, and microvascular disease than men. In those studies that have looked at sex differences in treatment response, sex-specific physiologic, pharmacokinetic, and pharmacodynamic differences appear to be the cause. Women have smaller hearts, higher heart rates, shorter cardiac cycle lengths, and longer QT intervals than men. CAD medical treatments such as antiplatelet agents, anticoagulants, β-blockers, and antithrombin agents may have different effects in women and men. Only 30% of percutaneous coronary interventions are performed in women. Women are less likely than men to undergo diagnostic angiography and are more likely to experience delays in treatment.