Aim To investigate the sCD40L levels in acute coronary syndrome and stable coronary heart disease and its relationship with serum lipids. Methods Enzyme linked Immunosorbent Assay (ELIA) was used to measure the serum soluble CD40 ligand (sCD40L). Results sCD40L level was significantly higher in patients with acute coronary syndrome (3.17±2.84 μg/L) than in control (1.19±1.05 μg/L, p<0.01) and in stable coronary heart disease patients (1.61±1.46 μg/L, p<0.05). Soluble CD40L level was significantly related to TG (r=0.23, p<0.05), apoB (r=0.248, p<0.05), and HDLC (r=-0.253, p<0.05). Conclusions This study showed that sCD40L level was elevated in ACS, suggesting the possible relation of CD40L to the pathogenesis of ACS and it may save as a potential marker of plaque stability.