Objective To investigate the expressions of insulin like growth factor binding protein -3 ( IGFBP-3 ) in serum and bronchoalveolar lavagae fluids ( BALF ) of patients with non-small cell lung cancer , and explore the clinical significance in dignosis and prognosis of lung cancer.Methods The bronchoalveolar lavagae fluids ( BALF ) were collected by bronchoscopy in 80 cases with non-small cell lung cancer and 14 healthy subjects.The expression of IGFBP-3 in serum and BALF were detected by immunoradioassay.Results The expression of IGFBP-3 in serum and BALF of lung cancer group were significantly lower than that of health group(Plt;0.05).IGFBP-3 levels were significantly lower in those patients with lymphoid node metastasis or metastasis or TNMⅢ-TNMⅣ than those without metastasis or TNMⅠ-TNMⅡ(Plt;0.05).In lung cancer group,the levels of the IGFBP-3 in serum and BALF had a significantly positive correlation(r=0.415,r=0.355,Plt;0.01).Conclusion The IGFBP-3 may play an important role in the development of non-small cell lung cancer and is valuable in dignosis and prognosis of lung cancer.