Genotype-guided warfarin dosing algorithms offer a rational method to optimize warfarin dosing and possibly lower adverse medication effects. Compared to people of European ancestry, diverse communities, such as African Americans and Asian population, have higher rates of warfarin-related adverse events and larger dose variability, which suggests that these groups could stand to gain more from improved warfarin dose estimate. However, data from prospective randomised studies, which make up a large portion of the literature on genotype-guided warfarin dose, are from individuals with European ancestry. The majority of the research in different groups assesses variations that are most prevalent in populations of European ancestry, despite differences in the frequencies and consequences of variants by race/ethnicity. Algorithms are unlikely to help a wide range of populations if they do not take into account variations that are significant across racial/ethnic groups. The development of racespecific or admixture-based algorithms may enable genotype-guided warfarin dosing algorithms that are superior to those seen in people with European ancestry in particular racial/ethnic groups. The evaluation of current research assessing the therapeutic usefulness of genotype-guided warfarin dose should take these observations into account. For the practical use of warfarin pharmacogenomics to be successful, careful consideration of race and ethnicity as well as more research aimed at refining warfarin dosing algorithms across race and ethnic groups will be required. The results of the warfarin pharmacogenomics have important implications for Pharmacogenomic testing, underscoring the significance of considering race and ethnicity when identifying gene-drug interactions and developing therapeutic recommendations for pharmacogenetic testing.