Thiopurines, one kind of immunosuppressants, represent an effective and widely prescribed therapy in clinic. Howev-er, the narrow therapeutic window and pharmacokinetic individual differences are always the problems in the clinical application of these drugs. Many factors can affect the metabolism and pharmacological effects of thiopurines, and the genetic polymorphisms of relat-ed metabolic enzymes involved in the metabolic process are considered to be the main factors. Recently, there is growing attention to the influence of the pharmacogenetics of related metabolic enzymes on the pharmacokinetics and pharmacodynamics of thiopurines. Therefore, based on the literature data, this review summarizes the correlation between the genetic polymorphisms of related metabolic enzymes ( TPMT, ITPA, GST, HPRT, XO, IMPDH and GMPS) and efficacy and side effects of thiopurines in order to provide guid-ance for the individualized thiopurine treatment in the clinical practice.