This study was undertaken to evaluate the effects of health education and anti-Clonorchis campaign conducted in Kyungpook Province and to compare the prevalence of Clonorchis sinensis among the residents in the same areas for the period 1964-1976. Both surveys were made on all age groups of residents ranging from 0 to over 60 years of age. They were examined using primarily intradermal tests with Clonorchis and Paragonimus antigens and followed by stool examinations. The definitive diagnosis of clonorchiasis was made on the recovery of Clonorchis eggs from the stools. A marked reduction in the prevalence was encountered in the youngest age group, but there is no significant difference in the older age groups. The overall prevalence rate for clonorchiasis was reduced from 27.7 to 19.6 per cent in a period of 10 years. It is found that clonorchiasis is less prevalent in Kyungpook Province than it was a decade ago and it continued to decline.
