The risk of the development of colon cancer in relation to a western diet was studied in a community-based cohort in Japan. From 1992 to 2000, 13,894 men and 16,327 women were followed. In men, high consumption of processed meat increased the risk in comparison with low consumption (adjusted RR=1.98, 95% CI: 1.24-3.16). In women, daily coffee drinkers had a reduced risk in comparison with individuals who never or rarely drank coffee (adjusted RR=0.43, 95% CI: 0.22-0.85). The findings suggest the possible linkage between a western diet and risk of colon cancer.