Objectives: The purpose of this research was to compare coronary obstruction between clinically similar African Americans(AA) and white persons undergoing coronary angiography. Background: African Americans have higher rates of coronary death than whites, but are less likely to undergo coronary revascularization. Although differences in coronary anatomy do not explain racial difference in revascularization rates, several studies of clinically diverse persons undergoing coronary angiography have found less obstructive coronary disease in AA than clinically similar whites. Methods: We studied 52 AA and 259 white male veterans who had both a positive nuclear perfusion imaging study and coronary angiography within 90 days of that study in five Department of Veterans Affairs hospitals. We used chart review and patient interview to collect demographics, clinical characteristics, and coronary anatomy results. Before angiography, we asked physicians to estimate the likelihood of coronary obstruction. Results: The treating physicians’estimates of coronary disease likelihood were similar for AA(79.5%) and whites(83.0%); AA were less likely to have any coronary obstruction(63.5%vs. 76.5%, p=0.05) and had significantly less severe coronary disease(p=0.01) than whites. African Americans continued to be less likely to have coronary obstruction in analyses controlling for clinical features, including the physicians estimate of the likelihood of coronary obstruction. Conclusions: These results suggest that AA have less coronary obstruction than apparently clinically similar whites. Further studies are required to confirm our findings and better understand the paradox that AA are less likely to have obstructive coronary disease and more likely to suffer mortality from coronary disease. Objectives: The purpose of this research was to compare coronary obstruction between clinically similar African Americans (AA) and white persons undergoing coronary revascularization. differences in coronary anatomy do not explain racial difference in revascularization rates, several studies of clinically diverse persons undergoing coronary angiography have found less obstructive coronary disease in AA than clinically similar whites. Methods: We studied 52 AA and 259 white male veterans who had both a positive nuclear perfusion imaging study and coronary angiography within 90 days of that study in five Department of Veterans Affairs hospitals. We used chart review and patient interview to collect demographics, clinical characteristics, and coronary anatomy results. Before angiography, we asked physicians to estimate the likelihood of coronary obstr Results: The treating physicians’ disease of coronary disease likelihood were similar for AA (79.5%) and whites (83.0%); AA were less likely to have any coronary obstruction (63.5% vs. 76.5%, p = 0.05) and had significantly less severe coronary disease (p = 0.01) than whites. African Americans continued to be less likely to have coronary obstruction in analyzes control for clinical features, including the physician’s estimate of the likelihood of coronary obstruction. Conclusions: These results suggest that AA have less coronary obstruction than apparently clinically similar whites. Further studies are required to confirm our findings and better understand the paradox that AA are less likely to have obstructive coronary disease and more likely to suffer mortality from coronary disease.