In the past, differences in opinion among professional groups about colorectal cancer screening have been a barrier to colorectal cancer prevention. It is clear that screening for colorectal cancer is currently practiced by fewer than 20% of American adults. However, a growing consensus now exists that even though we do not yet have trial data to compare precisely the various methods for screening, there is now both a compelling case for screening and a reasonable set of methods that clinicians and patients can consider. By applying the knowledge we already have, it is likely that most of the deaths from colorectal cancer in the United States could be prevented.