Numerous basic research indicates that activation of peroxisome proliferator activated receptors(PPAR) family, consisting of PPAR-alpha, -delta and –gamma, may beneficial effects on initiation and progression of arterial atherosclerosis. Especially each of PPARs is known to influence the lipid uptake and efflux, inflammatory mediator production in macrophage. Aim: To explore the activities of each subfamily protein in blood monocytes of patients with severe atherosclerosis comparing with those of mild or disease free subject determined by coronary angiography. Method: Monocyte rich buffycoat layer was isolated from blood samples of seventeen patients with two or three coronary artery disease and seventeen control subject. Immediately extracted mRNAs were analyzed by quantitative real time reverse transcription polymerase chain reaction using subfamily specific primer Results: mRNA expression of PPAR-alpha and –delta were markedly decreased in patients with coronary artery disease than in mild or disease-free control subject. However, mRNA expression of PPAR-gamma showed statistically no significant difference between both groups (Table 1). The expression level of PPAR-alpha, PPAR-delta and PPAR-gamma showed the positive correlation ( PPAR-alpha and –delta, 款=0.61, P<0.0001; PPAR-alpha and –gamma, 款=0.715, P<0.0001; PPAR-delta and –gamma, 款=0.71, P<0.0001) Conclusion: This result suggest that decreased activity of PPAR-alpha and PPAR-delta in human monocytes may be related with atherosclerotic disease progression