BACKGROUND: EGFR is one of the initial step in signal transduction pathway about multistep carcinogenesis. It is homologous to oncogene erbB-2 and is the receptor for EGF and TGF alpha. EGFR has important role in the growth and differentiation of tumor cells. So, EGFR in non-small cell lung cancer was examined to search for possible evidence as clinical prognostic factor. METHODS: To investigate the role of EGFR in lung cancer, the author performed immunohistochemical stain of EGFR on 57 resected primary non-small cell lung cancer specimens. And the author analyzed the correlation between EGFR expression, clinical parameters, S and G1 phase fraction and survival. RESULTS: 1) EGFR were detected in 56% of total 57 patients (according to histologic type, squamous cancer 50%, adenocarcinoma 63%, large cell cancer 75%) (according to TNM stage, stage I 64%, stage II 38%, stage III 55%) (according to cellular differentiation, well 50%, moderately 52%, poorly 65%). All differences were insignificant. 2) Using the flow cytometric analysis, mean S-phase fraction of EGFR (+) and (-) group were 22.3(+/-10.5)%. 18.0(+/-10.9)% (p>0.05), mean G1-phase fraction of EGFR (+) and (-) group were 68.4(+/-11.6)%, 71.1(+/-12.8)%, (p>0.05) 3) Two-year survival rate of EGFR (+) and (-) group were 53%, 84%, median survival time of EGFR (+) and (-) group were 26, 53 months. (p<0.05, Kaplan-Meier, generalized Wilcox) CONCLUISON: EGFR immunostaining may be a simple and useful method for survival prediction in non-small cell lung cancer.