Various transporters, expressed in the gut, liver, and kidney, are known to govern a drug's ADME, and their activities can be up- or down-regulated, and thus have significant consequences on the systemic and tissue exposures to drug substrates. However, transporter regulations are an emerging field with mechanisms that remain elusive. This symposium aims to highlight recent advances in our understanding of transcriptional, post-transcriptional, and post-translational modification mechanisms of transporter regulation, and their clinical relevance. Novel and translational tools, such as endogenous biomarkers and cynomolgus monkey models, have been utilized to investigate the regulatory effects on transporters in vivo.