We hypothesized that significant disparities in gender exist in the management of patients with non-ST-segment elevation (NSTE) acute coronary syndromes (ACS). Gender-related differences in the diagnosis and treatment of ACS have important healthcare implications. No large-scale examination of these disparities has been completed since the publication of the revised American College of Cardiology/American Heart Association guidelines for management of patients with NSTE ACS. Using data from the CRUSADE (Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the American College of Cardiology/American Heart Association Guidelines) National Quality Improvement Initiative, we examined differences of gender in treatment and outcomes among patients with NSTE ACS. Women (41% of 35,875 patients) were older (median age 73 vs. 65 years) and more often had diabetes and hypertension. Women were less likely to receive acute heparin, angiotensin-converting enzyme inhibitors, and glycoprotein IIb/IIIa inhibitors and less commonly received aspirin, angiotensin-converting enzyme inhibitors, and statins at discharge. The use of cardiac catheterization and revascularization was higher in men, but among patients with significant coronary disease, percutaneous revascularization was performed in a similar proportion of women and men. Women were at higher risk for unadjusted in-hospital death (5.6% vs. 4.3%), reinfarction (4.0% vs. 3.5%), heart failure (12.1% vs. 8.8%), stroke (1.1% vs. 0.8%), and red blood cell transfusion (17.2% vs. 13.2%), but after adjustment, only transfusion was higher in women. Despite presenting with higher risk characteristics and having higher in-hospital risk, women with NSTE ACS are treated less aggressively than men.