The epigenetic regulation of expression of genes involved in the absorption, distribution, metabolism, and excretion (ADME) of drugs contributes to inter-individual variability in drug response. Epigenetic mechanisms include DNA methylation, histone modifications, and miRNAs. This review systematically outlines the influence of DNA methylation on ADME gene expression and highlights the consequences for inter-individual variability in drug response or drug-induced toxicity and the implications for personalized medicine. Fisel P, Schaeffeler E, Schwab, M. Clin Pharmacol Ther. May 2016; 99(5):512-527.