The present study was undertaken to evaluate the prevalence rate of Taenia species infection and distribution of taeniasis caused by Taenia solium among Koreans in Seoul and Cheju Do In Korea during the period from August to December 1984. A total of 4,256 stool specimens from the students of Mapo Ku and 360 stool specimens from the inhabitants of Guro-Ku in Seoul was collected and examined by cellophane thick smear technique. On the other hand 1,015 stool specimens from the students of Jocheon Myun and 265 specimens from the students of Jocheon Myun and 265 specimens from the inhabitants of Aeweol Myun and Gujwa Myun in Cheju Do were also examined. The results were summarized as follows ; Four (0.1%) out of 4.256 students were positive and 2 (0.6%) out of 360 inhabitants in Seoul were positive (Table 1, 2). Positive rates of taeniasis in Cheju Do were 1.7% (17) out of 1,015 students and 12.5% (33) out of 5 villagers (Table 3, 4). In order to observe the distribution of Taenia solium infection, the scolex or a part of Taenia spp. were collected from the stool of positive cases by anthelmintic treatment. For the species identification, expelled proglottides were examined microscopically by the number of branches of the uterus, presence of vaginal sphincter or the accessory ovarian lobe etc. Three cases were infected with Taenia solium among 6 egg positive cases in Seoul. But only 1 case was infected with Taenia solium out of 7 students taking anthelmintics voluntarily by recommendation of Korean Association for Parasite Eradication (KAFPE). On the other hand, among 32 cases of egg positive cases of this study and 26 cases of KAFPE in Cheju Do, 13 cases (22.4%) were infected with Taenia solium. But 13 cases who were not examined and complained expulsion of proglottides in their stool were infected with Taenia saginata (Table 5). Among 62 persons infected with Taenia saginata, only 4 cases did not know their infection of this worm. Rut in 17 cases with Taenia solium, 7 persons did not know their infection until stool examinations were performed (Table 6).