Colorectal cancer is the third most common cause of death due to cancer in Hong Kong. Most of these cancers are diagnosed at a late stage, when they are not amenable to curative treatment. Clinical trials have shown that screening for colorectal cancer using the faecal occult blood test can reduce death from colorectal cancer, but this test misses many cancers due to its inherent limitations. Double-contrast barium enema, flexible sigmoidoscopy and colonoscopy produce increasingly accurate results, at increasing cost. Selected population screening by faecal occult blood test, and targeted screening ofpersons at high risk using the more invasive tests, deserve consideration in Hong Kong. Amongst those at high risk are persons who have had rectal bleeding or colorectal adenomas, and those with one or more first-degree relatives with colorectal cancer or adenoma. Early diagnosis would allow more effective treatment to be given, without the need for a colostomy, and give better odds for survival and quality of life.