Prognostic value of p53 protein expression in node-negative lung adenocarcinoma is still controversy. The expression of p53 protein was examined immunohistochemically in lung adenocarcinoma using monoclonal antibody BP53-12. A total 131 cases of primary lung adenocarcinoma were examined. Relationship between expression of p53 protein and clinicopathologic factors were studied. Overexpression of p53 protein was found in 19 patients (14.5%). Univariate and multivariate analysis showed that overexpression of p53 protein was an independent prognostic factor in node-negative lung adenocarcinoma. p53 alteration could be a valuable predictor for prognosis in node-negative lung adenocarcinoma.