Aim To analyse osteoprotegerin(OPG) and brain natriuretic peptide(BNP) levels in patients with non-ST elevation acute coronary syndrome(NSTE-ACS),in relation to clinical presentation and to coronary coronary artery disease. Methods 192 consecutive patients were classified into three groups: stable angina(SA) group,unstable angina/non-ST elevation myocardial infarction(NSTE-ACS) group and control group,OPG and BNP levels were measured.OPG and BNP were compared in relation to the number of coronary artery disease,and to the stenoses degree by Gensini score. Results OPG levels were higher in all coronary artery disease patients compared to controls(P><0.01),however NSTE-ACS patients had higher OPG level with respect to SA patients(P><0.01).BNP levels were higher in NSTE-ACS patients compared to controls and SA patients(P><0.01).BNP levels was significantly higher in multivessels compared with 1-vessel disease(P><0.01).A positive relation was found between OPG levels and Gensini score(r=0.64,P><0.001).Only a mild correlation was found between BNP and Gensini score(r=0.45,P><0.01).Multiple regression analysis showed that OPG and BNP levels were independently and positively associated with the presence of coronary disease(P><0.01). Conclusions NSTE-ACS patients show high OPG levels.OPG is related to the number of coronary artery disease,which suggest its involvement in the coronary artery disease progression.BNP is also increased during NSTE-ACS and more associated to the scope and severity of ischemia.