BACKGROUND: Tumor angiogenesis is required for tumor growth and metastasis. In this study, we investigated the correlation between the intensity of angiogenesis and stage, nodal status, histologic type, metastasis and survival rate of non-small cell lung cancer. METHOD: Formalin fixed, paraffin embedded surgical specimens of 45 patients who had surgically resected primary non-small cell lung cancers without pre or post perative adjuvant chemotherapy or radiotherapy were examined. The microvessel count(MVC) was demonstrated by immunohistochemical staining for CD31(platelet ednothlial cell adhesion molecule, PECAM). RESULTS: Microvessel counts(MVCs)in stage IIIA and IIIB were higher than in stage I and II(p<0.05). The MVC in patients with lymph node metastasis was higher than that in patients without lymph node metastasis, although the difference was not statistically significant(p>0.05). However, in adenocarcinoma, the MVC in patients with lymph node metastasis was significantly higher than that seen in patients without lymph node metastasis(p<0.05). The MVC in adenocaricinoma was higher than that in squamous cell carcinoma(p<0.05). The difference between the MVCs of adenocarcinoma and squamous cell carcinoma was not statistically significant in stage Iand II or NO stage(p>0.05). However, in stage IIIA and IIIB or N1~3 stage, the MVC in adenocarcinoma was higher than that in squamous cell carcinoma(p<0.05). MVC was more increased when metastasis developed within 12 months. In the same histologic type and stage, the duration of survival time in patients with high MVC was shorter than in patients with low MVC, however the difference was not statistically significant(p>0.05). The survival rate in patients with high MVCs was lower than that in patients with low MVCs(P<0.05). CONCLUSION: In non-small cell lung cancer, MVC correlated relatively well with pathologic stage, nodal status (limited in patients with adenocarcinoma), histologic type, postoperative metastasis and survival rate. However, in the same histologic type and stage, MVC was not significantly related to the duration of survival. Therefore the assessment of the intensity of angiogenesis in non-small cell lung cancer may be helpful in predicting prognosis and in selecting patients for systemic adjuvant therapy of potential metastasis according to the results.