Cancer disparities in incidence and death rates exist among various racial and ethnic groups. These disparities are thought to be due to socioeconomic status, culture, diet, stress, the environment, and biology. Biological functions, such as epigenetic processes, are affected by all these causal factors and extend throughout the life course. Epigenetic processes, in particular DNA methylation, may play a role in the induction of phenotypes with increased cancer risk due to exposure to these multiple factors. DNA methylation is known to cause changes in gene expression of key regulatory genes in cancer. There are limited studies in which epigenetic changes have been explored to address cancer disparities in various racial and ethnic populations. These few studies have reported significant epigenetic differences in various racial and ethnic groups that could account for the differences seen in tumor initiation, progression, aggressiveness, and outcome of these cancers. Genes differentially methylated among these racially and ethnically diverse populations were involved in important cellular functions, such as tumor growth, tumor suppression, hormone receptors, and genes involved in tumor metastasis. Epigenetic research with the advancement in technology has helped identify biomarkers, therapeutic targets, and understand cancer causation in the general population. Unfortunately, these advances in technology have not been applied to explore the basis for cancer health disparities. More research in epigenetics is needed that will enhance our understanding of the determinants of cancer across various diverse populations and ultimately reduce cancer health disparities.