Few studies have addressed the relation between dietary patterns and colorectal cancer in Japan. We investigated dietary patterns in relation to colorectal cancer risk in a community-based case–control study. The association with dietary patterns was also examined for different sites of colorectal cancer. Data were derived from the Fukuoka Colorectal Cancer Study, including 800 cases and 775 controls interviewed from September 2000 to December 2003. The cases were admitted to one of the participating hospitals for the first surgical treatment during this period. We identified dietary patterns using principal component analysis of intakes of twenty-nine items of food groups and specific foods. Quartile categories of each dietary pattern were used, and non-dietary lifestyle factors and total energy intake were adjusted for in the analysis. We identified three dietary patterns: prudent, high-fat and light-meal patterns. The prudent dietary pattern characterised by high intakes of vegetables, fruits, seafoods and soya foods showed a nearly significant protective association with the overall risk of colorectal cancer (trend P = 0·054), and it was statistically significantly related to a decreased risk of distal colon cancer (trend P = 0·002), but not to that of either proximal colon or rectal cancer. The high-fat and light-meal dietary patterns were not materially related to the overall or site-specific risk of colorectal cancer. In summary, a prudent dietary pattern was associated with a decreased risk of colorectal cancer, especially with that of distal colon cancer, in a fairly large case–control study in Japan.