Information from Blacks and Whites interviewed in a case-control study of tobacco-related diseases was analyzed to identify explanatory factors for racial differences in smoking habits. Blacks were three times more likely to be light vs heavy smokers. This association did not differ according to such variables as cigarette preference, degree of inhalation, or quitting. The association of race and light smoking was present in both current and ex-smokers. Sociodemographic or smoking-related characteristics do not appear to explain racial differences in smoking habits. Future studies should focus on cultural factors influencing smoking behavior.