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.