It is still controversial whether restriction fragment length polymorphism (RFLP) of the L-myc proto-oncogene is correlated with the prognosis in lung cancer patients or not. On the other hand, we have shown that the histological pattern of invasion is correlated with the prognosis of surgically treated patients of lung adenocarcinoma. In this study, the L-myc RFLP was compared with the histological pattern of invasion and the prognosis in 63 Japanese lung adenocarcinoma patients to evaluate the L-myc RFLP as a prognostic marker. Although the histological pattern of invasion was correlated with the prognosis, no correlation was observed between the L-myc RFLP and the prognosis. No association was found between the L-myc RFLP and the histological pattern of invasion in this study. Our results showed that the L-myc RFLP is not a strong prognostic marker compared with histologic pattern of invasion in lung adenocarcinoma.