The Japanese Society of Fish Pathology held a symposium entitled “Current topics on protozoan and other parasitic diseases of fish in Japan” in Miyazaki on 27th September 2001. This symposium was aimed to have an overview of the current status of the researches on protozoan and other parasitic diseases of fish in Japan. Following a keynote presentation of the same subject in the world, two emerging diseases of marine fish in Japan, i.e. emaciation disease in tiger puffer and anemia in Japanese flounder, were introduced. Three species of myxosporeans are responsible for the former disease, and a monogenean Neoheterobothrium hirame causes the latter. The resent researches on kudoosis amami in yellowtail and amberjack, Heterobothrium infection in tiger puffer and blood fluke disease in yellowtail were also presented. The importance of the prevention against the fish protozoan and other parasitic diseases was discussed.