The aim was to characterize non-participants and to investigate reasons for non-participation in a health survey in Kin-Hu township, Kinmen, Republic of China. The non-participants represented 25.6% of the target population of 4,451 registered residents aged 30 and older. Baseline demographic characteristics and two-year mortality for the participants and non-participants were compared. A house-to-house visit was attempted to all of the non-participants for reasons of refusal. The mean age of the non-participants was significantly older than that of the participants (54.3 versus 48.5 years, p < 0.001). The response rate for women was significantly higher than that for men (77.2% versus 71.6%, p < 0.001). The probability of death was significantly different between the two groups (1.2% versus 8.8% for participants and non-participants, respectively, p < 0.001). Major reason for not having participated in the health survey was 'not notified or informed of the examination' (32.7%). These data suggest that non-participants were less healthy.