Parasitic disease is still important subject in the field of infectious diseases in Korea considering it's number and morbidity. Recently there was conspicuous reduction of parasitic disease in terms of soil-transmitted nematodiasis, but parasitism affecting organs other than intestinal tract is still a considerable problem. This survey covers the parasitic diseases cross-sectioned at a pathology laboratory of a referral hospital, trying to elucidate the significance of its relative frequency and also to describe some histopathological changes made by different parasites. Entire pathological materials of parasitic diseases, that were referred, examined and confirmed at the Department of Pathology, Seoul National University Hospital from 1968 to 1987, were used for the study. There was a total of 594 cases of tissue parasitic diseases. This number accounted for 0.33 per cent of total accessions of surgical pathology. There occurred average 30 cases of tissue parasitic disease each year at this Hospital. Protozoal diseases were constituted of 15 cases of amebiasis, 7 cases of leishmaniasis (imported) and 5 cases of Pneumocystis carinii infections. Among helminthic infections cysticercosis was the most common (425 cases), and was followed by paragonimiasis (35 cases), sparganosis (31 cases), clonorchiasis (32 cases) and ascariasis (16 cases). In addition there were 4 cases of anisakiasis, 2 cases of fascioliasis, 2 cases of echinococcosis (imported) and a case of strongyloidiasis and a case of metagonimiasis respectively. It is emphasized that imported parasitic diseases such as leishmaniasis and hydatid disease become steadily found nowadays. Schistosomiasis is another possible imported disease, but not found in this series. And certain cestodiasis particularly cysticercosis and sparganosis should be the subjects of epidemiologic re-evaluation in view of steady occurrence of their morbidity.