Peroxisome proliferator-activated receptors (PPARs) are nuclear transcription factors that regulate gene expression in response to activation by specific ligands including insulin sensitizing thiazolidinedione and lipid-lowering fibrates. Recent work has identified PPARalpha and PPARgamma expression in vascular cells and established a role for these receptors in the regulation of genes relevant to atherogenesis. The following review will focus on the role of PPAR activation in the vasculature and discuss the potential clinical implications of these findings.