Background: Epidermal growth factor receptor (EGFR) mutation plays a key role in the carcinogenesis of lung adenocarcinoma. However little is known about the environmental and life style factors, in particular dietary habits, influencing EGFR mutations. Methods: Between July 1999 and July 2004, 1995 consecutive patients with lung cancer were prospectively assessed on dietary habits using the semiquantitative Food Frequency Questionnaire (FFQ) which contains questions regarding 138 foods in National Cancer Center Hospital East. EGFR mutations (exon 19 deletion and exon 21 L858R) were examined in 298 adenocarcinomas of whom by direct sequence method. The intake of nutrients was calculated with standard tables of food composition in Japan, 5th revised and enlarged edition. The differences of consumption of 22 food groups and 45 nutrients (energy-adjusted values using the residual method) between EGFR mutations positive (156 patients) and negative (142 patients) were investigated by multivariate logistic regression model adjusted for gender, age, smoking status and body mass index, regarding patients without EGFR mutations as control cases. Results: The grain and carbohydrate consumption of patients with EGFR mutations was significantly lower than patients without EGFR mutations. The multivariate-adjusted odds ratios and 95% confidence intervals for the third tertile of grain and carbohydrate consumption of patients with EGFR mutations in comparison with the first tertile were 0.46 (0.24-0.87) (p for trend =0.021) and 0.44 (0.23-0.85) (p for trend =0.016), respectively. Conclusions: In the present study, it was suggested that the lower consumption of grain and carbohydrate correlated with EGFR mutations. Further research to investigate the influence of these dietary components and habits on carcinogenesis of lung adenocarcinoma with EGFR mutations is warranted.