OBJECTIVE To determine whether the extent of coronary obstructive disease is similar among black and white patients with acute coronary syndromes. DESIGN Retrospective chart review. PATIENTS We used administrative discharge data to identify white and black male patients, 30 years of age or older, who were discharged between October 1, 1989 and September 30, 1995 from 1 of 6 Department of Veterans Affairs (VA) hospitals with a primary diagnosis of acute myocardial infarction (AMI) or unstable angina (UnA) and who underwent coronary angiography during the admission. We excluded patients if they did not meet standard clinical criteria for AMI or UnA or if they had had prior percutaneous transluminal coronary angioplasty or coronary artery bypass grafting. MEASUREMENTS AND MAIN RESULTS Physician reviewers classified the degree of coronary obstruction from blinded coronary angiography reports. Obstruction was considered significant if there was at least 50% obstruction of the left main coronary artery, or if there was 70% obstruction in 1 of the 3 major epicardial vessels or their main branches. Of the 628 eligible patients, 300 (48%) had AMI. Among patients with AMI, blacks were more likely than whites to have no significant coronary obstructions (28/145, or 19%, vs 10/155 or 7%, P = .001). Similarly, among patients with UnA, 33% (56/168) of blacks but just 17% (27/160) of whites had no significant stenoses (P = .012). There were no racial differences in severity of coronary disease among veterans with at least 1 significant obstruction. Racial differences in coronary obstructions remained after correcting for coronary disease risk factors and characteristics of the AMI. CONCLUSIONS Black veterans who present with acute coronary insufficiency are less likely than whites to have significant coronary obstruction. Current understanding of coronary disease does not provide an explanation for these differences.