Abstract: AIM: To evaluate the correlation between the levels of peroxisome proliferator-activated receptors δ (PPARδ) expression in peripheral blood monocytes and the serum levels of interleukin-6 (IL-6) and interleukin-10 (IL-10) in patients with acute coronary syndrome (ACS). METHODS: Peripheral blood monocytes were collected from 55 patients with ACS and 47 healthy controls. The PPARδ expression was detected by RT-PCR and the serum levels of IL-6 and IL-10 were measured by ELISA assay. RESULTS: The PPARδ expression levels were markedly reduced in peripheral blood monocytes from patients with ACS compared with those from healthy controls (P<0.01). The serum IL-6 level was significant higher while the IL-10 level was obvious lower in patients with ACS compared with those in controls (both P<0.01). The PPARδ expression level was negatively correlated to the IL-6 level (r=-0.413, P<0.05) and positively correlated to the IL-10 level (r=0.601, P<0.05). CONCLUSION: PPARδ may play a critical role in the pathogenesis of ACS.