To determine how current researchers address the use of race and ethnicity as variables in epidemiologic and public health studies, the authors conducted a comprehensive review of 1,198 articles published in the American Journal of Epidemiology and the American Journal of Public Health from 1996 to 1999. Seventy-seven percent (n = 919) of the articles referred to race or ethnicity. The number of variable categories ranged from 0 to 24, with an average of 3.14 per article. An enormous diversity of terms was used to describe the concepts of race and ethnicity as variables as well as to describe the categories used to assess these variables. Researchers frequently failed to differentiate between the concepts of race and ethnicity, to state the context in which these variables were used, to state the study methods used to assess these variables, and to discuss significant study results based on race or ethnicity. Continued professional commitment is needed to ensure the scientific integrity of race and ethnicity as variables. At a minimum, researchers should clearly state the context in which these valuable epidemiologic and public health study variables are being used, describe the method used to assess and categorize these variables, and discuss all significant findings.