Abstract: Objective To investigate the effects of proximal bronchial extension of hilar type nonsmall cell lung cancer (NSCLC) of different types, pTNM stages and expression of p53 protein and provide a clinicopathological basis for a curative resection. Methods :Eighty-six surgical specimens of primary hilar type NSCLC were collected for this study. Macroscopic and microscopic proximal bronchial invasion lengths were measured from bronchial resection margins to tumor edges. The expression of p53 protein was determined in all cases of primary hilar type NSCLC by immunohistochemical technique. Results :The invasion length of Adenocarcinomas at stage !a was the longest (1.91±0.36cm) and that of Squamous cell carcinomas at stage I b was the shortest (0.39±0.15cm). The positive expressions of p53 protein (0.87 ±0.49cm) was much longer than that of negative ones (0.53 ±0.32cm), which was significantly different (t=3.82, P<0.01). Conclusion :The extension of invasion is correlated with the histopathologic type of cancer, TNM classification and p53 expression, which are one of clinicopathological bases for a curative resection.