Abstract： Objective To study the effects of diabetes mellitus(DM)on fas receptor-induced cardiomyocytes apoptosis and inflammatory response in patients with acute myocardial infarction(AMI).Methods 70 patients with ST-elevated myocardial infarction were divided into two groups:without(n=36)and with diabetes mellitus(n=34).Strepavidin-biotin ELISA was used to examine the serum levels of sFas,sFasL,TNF-α and IL-6.Results As the concentrations of sFas and sFasL immediately after primary PCI were higher in patients of AMI with DM than without DM(4.18±0.86 vs 3.30±0.82 ng/ml,6.15±1.56 vs 4.34±1.37 ng/ml,respectively,P<0.01),so did the concentrations of TNF-α and IL-6(32.78±6.16 vs 20.54±9.17 pg/ml,75.28±19.60 vs 54.35±14.74 pg/ml,respectively,P<0.05).The concentrations of sFas,sFasL,TNF-α and IL-6 were higher in patients with killip 3,4 than in the patients with killip2,1(F=4.52,P<0.05).Conclusions Diabetes mellitus may accelerate cardiomyocytes apoptosis through activation of Fas/FasL system and aggravate inflammatory response in patients with acute myocardial infarction,which may be one of the reasons for severe conditions and ill prognosis in patients with acute myocardial infarction and diabetes mellitus.