The hypothesis that the evaluation of one's health as poor is associated with mortality, independent of the results of a standardized medical examination, was tested in the Kaunas-Rotterdam Follow-Up Study. In this study two cohorts, one consisting of 2452 Lithuanian males and one of 3365 Dutch males, aged 45-60, were screened for cardiovascular risk factors in 1973, using identical protocols, and were followed for about ten years. Self-rated health was assessed by two direct questions: 'How would you assess your own health?' and 'What do you think of your own health compared to that of other men of your age?' as well as by a Semantic Differential Test of 'My Health'. In both cohorts a negative evaluation of one's health was associated with mortality, controlling for past or present heart disease, cardiovascular risk factors, parental life span, socio-economic and marital status. Especially the data with regard to the comparative question indicate that self-rated health is associated with mortality in men living in two different socio-cultural systems. The date suggest that a weak sense of mastery may explain the association between health perception and mortality.