The success of a cancer detection programme depends on the co-operation of the target population. The aim of this study was to identify factors which might influence those at average and at higher risk of developing colorectal cancer to undergo a sigmoidoscopic screening test if offered. This was addressed by means of a household survey of individuals aged 40 years and over. Overall consent to undergo screening approximated 45%. There was a significant relationship between agreement to sigmoidoscopy and each of the following: age, marital status, educational level attained, and a previous episode of rectal bleeding. Individuals who had undergone sigmoidoscopy in the past were less willing to have the test performed again. Although individuals with a family history of bowel cancer in first-degree relatives perceived themselves as being more likely to develop colorectal cancer, this had no apparent impact on their willingness to have the test. The implications of these findings for community education programmes directed at colorectal cancer are discussed.