The incidence of colorectal cancer continues to increase or at least remains stable. Epidemiologic data are defining hereditary colorectal cancer as an important part of the spectrum. The most exciting recent development has been the identification of the adenomatous polyposis coli gene on chromosome 5, thought responsible for adenomatous polyposis coli. Increasing numbers of studies are further characterizing the gene as well as its mutations, found in polyposis patients, and are using gene markers to identify affected family members. Risk assessment for colorectal cancer continues to be refined. Patients with only a single small tubular adenoma may not have a significantly increased risk of subsequent colorectal cancer. Patients with chronic ulcerative colitis are at increased risk, but the optimal surveillance schedule, as well as whether surveillance reduces colorectal cancer mortality, remains undetermined. Fecal occult blood testing, recommended in most screening strategies, may have an unacceptably low sensitivity and high false-negative rate in screening studies. Screening by means of sigmoidoscopy may reduce mortality from cancer of the distal colon, and screening once every 10 years may be as efficacious as more frequent screening. The debate over whether colonoscopy or sigmoidoscopy should be used in screening continues. Proximal neoplasms do occur even when they are absent distally, but colonoscopy is more invasive and expensive than sigmoidoscopy. Results from large-scale prospective screening trials are eagerly awaited over the next several years. Until then, following the current recommendations is justified in high-risk groups as well as for average-risk individuals upon request, but it is probably not useful for large-scale general population screening.