Objective To understand the clinical significance and diagnosis value of serum interleukin-6(IL-6) levels in the patients with respiratory infection and non-small cell lung cancer(NSCLC).Methods The serum levels of IL-6 in 61 patients with NSCLC,and 36 patients with respiratory infection and 30 of the healthy was measured by enzyme-linked immunosorbent assay(ELISA).Results The data showed that mean serum IL-6 levels in patients with NSCLC was higher than in the healthy( P 0 05).Conclusion We consider that increased IL-6 level could be used as one of differential diagnostic marker of NSCLC;Serum IL-6 levels may be a reference of judging each stage of NSCLC and predicting prognosis.