Background Prior studies, usually conducted with the use of insurance databases, have shown differences in the use of cardiac procedures between black patients and white patients hospitalized with various types of coronary artery disease. However, few data are available in prospectively collected cohorts of patients with unstable angina or on the use of appropriate medications or interventions. Methods and Results We evaluated 2948 consecutive patients with unstable angina admitted to 35 hospitals across the United States in 1996, comparing nonwhite and white patients. Seventy-seven percent of patients were white, 14% were black, 4% were Hispanic, 1% were Asian, and 3% were other or unknown race. Differences were seen in coronary risk profile, with a higher incidence of hypertension and diabetes mellitus in nonwhites. Cardiac catheterization was performed less often in nonwhites compared with whites (36% vs 53%, P = .001). Even in patients meeting the criteria for appropriate catheterization in the Agency for Health Care Policy Research unstable angina guidelines, fewer nonwhites underwent catheterization (44% vs 61%, P = .001), but among these, fewer nonwhites had significant coronary stenosis (72% vs 90%, P = .001). However, among patients catheterized who had indications for revascularization, angioplasty and coronary artery bypass grafting were performed equally often in nonwhites and whites. Conclusions Current guidelines would recommend more aggressive use of cardiac catheterization for nonwhite patients. However, our findings suggest that racial differences may need to be included in the diagnostic and interventional algorithms. (Am Heart J 1999;138:1065-72.)