The Department of Parasitology offers opportunities and facilities for studies and educations in “Medical Parasitology”, including a wide range of parasitic diseases and medically important insects and other animals (Medical Entomology and Zoology). Members of the Department educate the students, and investigate the host-parasite relationships of protozoans and helminthes, from different views of the pathobiological, immunological and epidemiological points. In Japan, nowadays, clinical cases caused by parasitic organisms decreased notably, after eradicating many parasitic diseases prevalent country-wide before; they were ascariasis, hookworms, filariasis, schistosomiasis, malaria and so on. Recently, however, imported and/or newly emerged cases of parasitic diseases are increasing gradually, because of various factors of environmental, socio-medical and socio-economical changes. On the other hand, in tropical and subtropical countries of the world, many persons suffer from parasitic diseases, as shown by WHO reports. Therefore, studies and educations on parasitic diseases at medical school should be emphasized, especially in the international medical cooperation, leading to the comprehensive understanding of the importance of such diseases.