In the world of medicine and therapeutics, race and ethnicity might reasonably be considered as biomarkers or predictors of drug effect. Recognizing that all biomarkers are imperfect, self-reported race can be viewed as a complex combination of genetic and nongenetic biomarkers that is used by prescribing physicians as a predictor of drug effect. The use of pharmacogenetic markers, such as haplotypes, patterns of candidate genes, and specific genotypes, may be used to enhance the precision of race-based prescribing and, when possible, should be combined with nongenetic predictors of responses to optimize the individualization of therapy.