Abstract: Objective : To study change and function of serum soluble Fas (sFas) level in patientswith nasopharyngeal carcinoma(NPC). Methods Enzym Linked-Immun-Sorbent Assay(ELISA) wasavailable to detect the level of serum sFas in 56 patients with NPC (NPC group) and 21 normal controlsubjects (control group). Results : 1) Serum sFas level in NPC group was significantly higher than thatof control group (P<0.01), Serum sFas level in patients of stageⅢ orⅣwas significantly higher thanthat of patients of stage ⅠandⅡ (P<0.01), and serum sFas level in patients of stage Ⅲwas signifi-candy higher than that of patients of stageⅣ(P<0.01). 2) Serum sFas level in NPC patients with posi-tive EBV-VCA-IgA obviously increased, compared with NPC patients with negative EBV-VCA-IgA(P<0.01). Conclusions : Serum sFas may serve as a novel marker for nasopharyngeal carcinoma, It may beone of the the mechanism through which NPC cells escape from the immune attack.