From July 1974 to May 1979, 573 black persons in the Coronary Artery Surgery Study (CASS) underwent coronary angiography. Compared with 23,008 white persons, larger percentages of black men and women were current smokers and reported a history of systemic hypertension. Despite the presence of chest pain, larger percentages of blacks had normal coronary arteries by angiography than did whites. The 5-year age- and sex-adjusted survival rate was 88% for whites and 82% for blacks (p less than 0.0001). Cox analysis indicated that black race was related to poorer survival in the medical group (p = 0.0006) but not in the surgical group (p = 0.28). For blacks, surgical therapy was related to a better survival rate (p = 0.009). These results raise questions concerning the effects of excess cigarette smoking and systemic hypertension and the role of coronary artery bypass surgery on survival of black persons.