The intradermal (ID) test has been widely used in Korea and several reports about the results of the ID test are known. We examined the egg of Clonorchis sinensis (C.s.) by ID test in 443, stool's egg-counting technique in 79 and direct smear (cellophane thick smear technique) in 1204 subjects. The results are as follows: 1. The positive rate of C.s. was 3.8% out of 1304 persons. 2. The sensitivity of ID test was 82.1% out of 39 persons and the specificity was 64.6% out of 404 persons. 3. The false positive of ID test was 35.4% out of 404 persons and, the false negative was 17.9% out of 39 persons. Intradermal test is a rapid, sensitive and useful supplementary diagnostic tool for the detection of Clonorchiasis infection and must be used as screening test with direct smear of stool but cross reaction with other helminth infections and moderate false reaction are the main disadvantages in its practical application.