Background: Tumor angiogenesis is the growth of new vessels toward and within tumor. It has been demonstrated that the growth of tumor beyond a certain size requires angiogenesis and it is closely involved in tumor progression and metastasis. The finding that intensity of neovascularization correlates independently with metastasis may lead to identification of patients in whom radical surgery should be supplemented by systemic treatment. Method: We have collected paraffin blocks of bronchoscopic biopsy of patients with non-small cell lung cancer. We highlighted the vessel by staining endothelial cell with JC70 monoclonal antibody(to CD31) immunohistochemically and counted microvessels under 200 X field using light microscopy. Results: 1) The mean microvessel count was 32.7+/-20.8 (9-96) in total 29 cases. 2) There were no correlations between microvessel counts and pathologic cell type, T staging, node metastasis(N) and hematogenous metastasis(M) (p>0.05). 3) The median follow-up duration was 15 months(2-46) and there was no correlation between the microvessel counts and survival rate of lung cancer patients (p>0.05). Conclusion: Tumor angiogenesis seems to be an important prognostic factor suggesting the probability of metastasis. But the microvessel count in the bronchoscopic biopsy specimen was inadequate and very limited. There has been no data about angiogenesis of lung cancer in korea yet. So the study of tumor angiogenesis using resected lung tumor specimen would be demanded.