The aim of this study was to assess the test-retest reliability of a measure of perceived general health by sex and age. The study analyzed data from the nationally representative Mini-Finland Health Survey of 8000 adults aged 30 and over. The subjects were invited to attend a personal health interview and a health examination in 1978-1980. Altogether 7217 persons participated. Perceived general health was measured at the personal health interview and in the self-administered questionnaire 1-6 weeks apart. The identical questions were: how would you assess your current health? The response alternatives were good, fairly good, intermediate, fairly poor, poor and cannot say. This study showed that among men and women unweighted agreement of the 'good-intermediate-poor' categorization of perceived health was around 70% and unweighted kappa-values were around 0.5. Only in the oldest age-group (75+) reliability declined below these levels. The fair or good reliability of perceived health observed in this study gives additional confidence for using this general measure of overall health status in future research.