Abstract: Objective: To explore the relationship between level of serum soluble Fas(sFas) and acute coronary syndrome(ACS).Methods: The level of sFas was measured in the sera from 22 patients with ACS and 10 controls by enzyme-linked immunosorbent assay(ELISA).The cardiac tropnin I(cTnI) of 21 ACS patients were measured at the same time.Results: The mean level of serum sFas was significantly higher in the patients with ACS than that of the controls(P<0.01).No difference was found between the groups with increased(MI) cTnI and normal(UA) cTnI in patients with ACS(P>0.05).Conclusions: High level of serum sFas is related to ACS,which may play an important role in the rupture of vulnerable atheromatous plaque.