Results In analyses including 1953 patients with colorectal cancer and 2015 controls, the use of statins for at least five years (vs. the nonuse of statins) was associated with a significantly reduced relative risk of colorectal cancer (odds ratio, 0.50; 95 percent confidence interval, 0.40 to 0.63). This association remained significant after adjustment for the use or nonuse of aspirin or other nonsteroidal antiinflammatory drugs; the presence or absence of physical activity, hypercholesterolemia, and a family history of colorectal cancer; ethnic group; and level of vegetable consumption (odds ratio, 0.53; 95 percent confidence interval, 0.38 to 0.74). The use of fibric-acid derivatives was not associated with a significantly reduced risk of colorectal cancer (odds ratio, 1.08; 95 percent confidence interval, 0.59 to 2.01). Self-reported statin use was confirmed for 276 of the 286 participants (96.5 percent) who reported using statins and whose records were available.