Objectives.: This study compared the rates of coronary artery bypass graft surgery and 15-year survival for men and women after initial medical or surgical management. Background.: There has been concern that women with coronary artery disease are managed differently than men and that men and women have a different prognosis. The Coronary Artery Surgery Study (CASS) registry is a large data base of well characterized patients with long-term follow-up. Methods.: Patients underwent cardiac catheterization at 1 of 15 hospitals during 1974 to 1979. Bypass surgery rates were based on 12,452 men and 2,366 women. Survival results were based on 6,018 men and 1,095 women with operable coronary artery disease and initial medical management and 6,922 men and 1,291 women initially managed surgically. Results.: At 15 years, bypass surgery rates were 75% for men and 72% for women (p = 0.91). The rates remained similar after adjustment for clinical and angiographic variables. The 15-year survival rate was 50% for men and 49% for women with initial medical treatment (p = 0.53) and 52% for men and 48% for women (p = 0.004) with initial surgical treatment, a difference similar to that for operative mortality (men 2.5%, women 5.3%, p < 0.0001). Survival was improved by bypass surgery in most subgroups, with largest relative risks for high risk patients. Relative risks were similar for men and women. Conclusions.: The rate of bypass surgery did not differ between men and women. There were few differences in the survival of men and women. In general, both men and women with initial surgical treatment survived longer, although benefits were clinically and statistically significant only in those at high risk. The benefit was similar in both men and women. © 1995 North American Society of Pacing and Electrophysiology; American College of Cardiology; American Heart Association, Inc.; and European Society of Cardiology.