Aim To explore the relationship between the levels of tumor necrosis factor related apoptosis inducing ligand(TRAIL) and death receptor 5(DR5) and acute coronary syndrome(ACS).Methods The 62 patients with coronary artery disease were divided into two groups:40 in the ACS group and 21 in the stable angina pectoris(SAP) group.Twenty-two healthy volunteers served as normal coronary artery(NCA) group.Plasma TRAIL and DR5 levels from these people were assayed by enzyme-linked immunosorbent assay.Reverse transcription polymerase chain reaction was used for the detection of TRAIL and DR5 mRNA of ascending aortas from 22 subjects,of which 8 were from the ACS group,7 from the SAP group and 7 from the NCA group.Results Plasma TRAIL levels were significantly increased in the ACS group(p<0.001).Patients with ACS had a markedly greater plasma DR5 level than those with NCA(p<0.05).Plasma levels of both TRAIL and DR5 in patients with 3-vessel involved ACS were significantly higher than those in patients with 1-vessel(p<0.05).The patients with 3-vessel involved ACS had markedly raised plasma TRAIL levels when compared with the patients with 2-vessel(p<0.05).In the 2-vessel group,only plasma DR5 levels had a statistical significance greater than those in the 1-vessel group(p<0.05).Logistic stepwise regression analysis revealed that odds ratio of TRAIL is 1.012(P=0.002).Ascending aortas from the ACS group exhibited markedly higher TRAIL expression as compared with those from the SAP and NCA group(p<0.05).Conclusions Increased plasma TRAIL and DR5 levels are closely associated with the presence and severity of ACS.