The aim of the present study was to assess health related characteristics and reasons for participation on the <<check-up-cruise>>, second, to compare these variables with a representative Swiss Health Survey (SHS). Characteristics of the participants were collected cross-sectionally and afterwards compared with results of the SHS. Response rate was 74.6% (n = 206). Compared to the SHS population smoking rate and alcohol consumption were significantly lower and a doctor's visit within the last 12 months more frequent. Considerable differences in health related characteristics exist between our study and the SHS suggesting a self-selection of healthy people. Thus a potential health gain by this kind of medical prevention program is at least questionable.