OBJECTIVES: The objective of this study was to compare attenders’ and non-attenders’ preferences in relation to participation in lifestyle disease screening. METHODS: During a screening trial of about 25,000 male citizens between the age of 65 and 75, 2,119 invitees were sampled. The screening programme comprised a test for abdominal aortic aneurysm, hypertension and peripheral artery disease, with relevant follow up for positive tests. Prior to the test, attenders were given a questionnaire about their doubt and arguments in relation to the participation decision, including different willingness-to-pay (WTP) questions. Non-attenders were mailed a similar questionnaire. RESULTS: 70% responded to the questionnaire, which lead to a study sample of 1,053 attenders and 435 non-attenders. Among attenders, 5% had doubt about participation and the most frequent argument was that they did not want to know about the test result. Among non-attenders, 46% would reconsider attendance after further information, the main argument for doubt being the same as for attenders. Further arguments were self-perceived low risk and the trouble and costs associated with attending. Attenders valued the programme significantly higher than non-attenders but this was sensitive to exclusion of bidders who did not pass a simple test for internal consistency of the reported WTP. Doubt about participation was associated with significantly lower WTP among attenders whereas the opposite was the case for non-attenders. Amongst those in doubt, the WTP was the same for attenders and non-attenders. CONCLUSIONS: Up to half of the non-attenders appeared to have doubt about their decision, which presents a potential for increasing the participation rate. Non-attenders in doubt about their participation decision value the programme at a similar level as attenders in doubt, suggesting that non-attenders in doubt do not differ significantly in their base-line valuations from those of the individuals in doubt who choose to attend.