Tsutsugamushi disease is widely spread throughout Japan. A case of tsutsugamushi disease was seen in October, 1996. A 64-year-old male developed typical symptoms of tsutsugamushi disease with Rickettsia tsutsugamushi, after he returned to Japan from Cheju Island, Korea. Not only in Japan but also in other Asian countries including Korea, China, Taiwan, and Thailand, tsutsugamushi disease is one of the most important rickettsial diseases carried by ticks or mites. If a traveller returning from an Asian country has symptoms such as high fever, skin eruption, and lymphadenitis, we should suspect that he is suffering from tsutsugamushi disease and should search if he has an eschar on any area of his body. We should not forget that tsutsugamushi disease is an imported disease. Patients of tsutsugamushi disease often have hematological disorders. They are sometimes referred to the hematological section of the hospital. Hematologists should be familiar with this disease.