Aim To evaluate the correlation among the level of peroxisome proliferator-activated receptors δ(PPARδ) expression in peripheral blood monocytes,serum levels of transforming growth factor-β1(TGF-β1) and interleukin-1β(IL-1β) in patients with acute coronary syndrome(ACS). Methods Peripheral blood monocytes were collected from 55 patients with ACS and 47 healthy controls.The PPARδ mRNA expression was detected by reverse transcription polymerase chain reaction(RT-PCR),while the serum level of TGF-β1 and IL-1β were measured by enzyme linked immunosorbent assay(ELISA). Results The PPARδ mRNA expression level(0.13±0.09)was markedly reduced in peripheral blood monocytes from patients with ACS compared with healthy controls(0.34±0.08,P><0.01).The serum IL-1β level(142.7±39.3 ng/L)was significant higher while the TGF-β1 level(11.4±4.6 μg/L) was obvious lower in patients with ACS than controls(81.5±23.9 ng/L,26.3±10.5 μg/L)(both P><0.01).Furthermore,the PPARδ mRNA expression level was negatively correlated to IL-1β level(r=-0.437,P><0.05) and positively related to TGF-β1 level(r=0.598,P><0.05). Conclusion The PPARδ might play a critical role in the pathogenesis of ACS.