Seroepidemiological status of toxoplasmosis among the residents of Jeju island was surveyed and evaluated by ELISA with crude extract of Toxoplasma gondii. The sera of 2,348 residents (male 1,157 and female 1,191) were collected and checked for the IgG antibody titers, which showed 13.2% positive rate (309 sera). The positive rates were increasing gradually according to the age from 4.3% in teenage to 20.6% in seventies. The positive rates were significantly different between the sex by 16.2% for male and 10.2% for female (P<0.05). This positive rate of toxoplasmosis in Jeju island residents is regarded relatively higher than any other regions of Korea. And the high positive rate may be maintained continuously among Jeju island residents without any clear reasons until now but due to some parts peculiar socio-cultural tradition of Jeju island. Therefore, it is necessary to study further the epidemiology of toxoplasmosis of Jeju island.