Objective: To study the clearing effects about hemoperfusi associated with hemodialysis on middlemolecular substances in chronic hemodialysis patients.Methods: Sixty-eight patients with chronic renal failure(CRF) received hemoperfusion incombination with hemodialysis(HD+HP).Results: Plasma β2-MG and iPTH were measured in plasma in pre and post-treatment by means of radio immunoassay.Conclusion: Blood purification with hemoperfusion plus hemodialysis may decrease plasma β2-MG and iPTH level more efficiently than hemodialysis performed alone.