Objective To investigate the plasma level change of myeloperoxidase(MPO)in patients suffering from stable angina pectoris.Methods Five hundred and seventy three patients underwent elective coronary angiography in a bi-racial cohort study,which included 295 patients with stable angina peetoris(SAP)and 278 subjects served as control.Plasma level of MPO and traditional risk factors of coronary artery disease(CAD)were measured.Results MPO levels did not differ significantly between control group and SAP group[126.3(95.8-160.2)mg/L vs 123.6(97.4-150.0) mg/L P＞0.05].MPO levels were similar across ethnicity and gender[black male 119.6(94.8-146.9) mg/L,white male 124.6(99.9～154.6)mg/L,black female 124.0(93.3～152.3)mg/L and white female 127.5(95.3～159.8)mg/L],and were correlated positively with the levels ofⅦfactor(r= 0.251,P＜0.01),fasting plasma glucose(r=0.095,P＜0.05),triglyceride(r=0.186,P＜0.01), total cholesterol(r=0.081,P＜0.05),high-sensitivity C-reactive protein(r=0.123,P＜0.01) and fibrinogen levels(r=0.077,P＜0.01),negatively correlated with adiponectin level(r=-0.115, P＜0.01).Conclusions Plasma MPO level is not elevated in patients with SAP.This suggests that MPO is not a characteristic feature of SAP.There are also no significant relationships between different genders and between different ethnicities.