The aim of the present study was to evaluate to what extent lifestyle-related variables predict participation for flexible sigmoidoscopy (FS) screening when the compliance is relatively high. During 2001, a randomized sample of 6961 men and women, born between 1946 and 1950, were invited to have a flexible sigmoidoscopy screening examination. Attendees (n = 4111) were asked to fill in a questionnaire focusing on physical activity, body weight, smoking habits and diet. The questionnaire was sent by mail to non-attendees (n = 2628) and a randomized corresponding control group not invited to screening (n = 7000). Sixty-one percent attended for screening. The questionnaire response rate among attendees, non-attendees and controls was 97, 11 and 61%, respectively. Attendees were more physically active (P < 0.001), and showed more adherence to general dietary recommendations, compared with controls. Opposing their healthy exercise and dietary habits, however, attendees were more likely to be moderate smokers compared with controls. The present offer of FS screening, achieving a relatively high compliance rate, may have reached attendees using screening as a supplement to an already healthy lifestyle, but also those who seek amelioration through health checks for risks behaviour that they are perfectly well aware of, such as smoking.