Peroxisome proliferator-activated receptors (PPARs) are a member of transcriptional factor that regulates expression of several genes associated with glucose and lipid metabolisms. Some polymorphisms of PPARs gene have been reported, and the impacts of these polymorphisms are examined in patients with several metabolic disorders. The Pro12Ala polymorphism of the PPARgamma gene is studied extensively, and is known to be associated with increased insulin sensitivity and reduced risk for the development of diabetes. Such studies will help us to elucidate the role of PPARs on the development of metabolic disorders and to find new therapeutic approaches to these disorders.