The aim of this study was to determine whether the austerely living Trappist and Benedictine monks have a lower prevalence of a number of risk factors and health problems than the general Dutch population. A written questionnaire was submitted to monks of 7 monasteries. The response was 67 per cent (134 monks). The data were compared with data from the national Health Interview Survey of 1989, which used an almost identical questionnaire. Adjustment was made for differences in age and education. Monks consume less alcohol and tobacco and have a more austere diet. Their average Quetelet index is lower. The prevalence of cardiovascular disease is lower. On the other hand, monks more often report a number of other chronic diseases, physical complaints, and problems with activities of daily life. They more often have contact with general practitioners and with consultants. The lower prevalence of a number of risk factors among monks reflects their austere way of life. It is not certain whether the lower prevalence of cardiovascular diseases can be attributed to this way of life. The fact that, in general, health problems are more prevalent among monks suggests that changes in lifestyle do not necessarily lead to compression of morbidity.