Objective To investigate serum angiopoietin-2(Ang-2)levels in non-small cell lung cancer(NSCLC)and its clinical significance.Methods Patients with NSCLC(n=98)and healthycontrols (n=30)were recruited into this study.Serum Ang-2 levels were measured using enzyme-linked immunosorbent assays(ELISA).The results were compared between patients with ifferent tumor stages,metastasis status,and postoperative recurrence 1 year after surgery.Results Patients with NSCLC had higher Ang-2 levels[median 3 230.5 ng/L,range(1 231.6～4 612.5)ng/L ]than the control group [median 831.7 ng/L,range(592.4-1 701.1)ng/L,U=15,P<0.01].Serum Ang-2 levels in stage Ⅲpatients[median 2 311.7 ng/Lrange(1 512.9～3 530.7)ng/L]were significantly higher than stage I [median 1 593.6 ng/L,range(1 235.2～2 763.1)ng/L,H=27.66,P<0.01]and stage Ⅱ patients [median 1 581.4 ng/L,range(1 231.6～2 852.3)ng/L,H=27.66,P<0.01],but significantly lower than stage Ⅳ patients[median 3 808.2 ng/L,range(2 235.8～4 612.5)ng/L,H=65.6P<0.01].Serum Ang-2 levels were higher in patients with distant metastasis or postoperative recurrence than those without them.Conclusion Serum Ang-2 level in patients with NSCLC could be a useful marker for metastasis and postoperative recurrence.