Clinical features of tsutsugamushi disease (scrub typhus) were analyzed, based on 416 cases reportedin Japan in 1998. Three major clinical symptoms: eschar, fever and rash were found in 87%, 98% and 92% of the cases, respectively. Elevated levels of CRP, GOT, GPT and LDH were observedin 96%, 85%, 78% and 91%, respectively. These clinical and laboratory findings were observed in themajority of the cases and considered important for diagnosis. Disseminated intravascular coagulationdeveloped in 21 cases, indicating that scrub typhus can be life threatening. Lymphadenopathy wasobserved in 51% of the cases. Enlarged lymph nodes were limited to the local sites in 75% of theselymphadenopathy cases and most of these sites were adjacent to eschars . Most eschars werescabbed and located in the abdomen and the lower half of the body, especially the feet. This suggeststhat these parts are frequently exposed to tsutsugamushi mites. Furthermore, the skin is soft inthese parts and covered by cloth. These factors may make it possible for mites to keep biting withoutbeing noticed for several hours, long enough for rickettsial transmission. Interestingly, eschar andrash were absent in 14% and 8% of the cases, respectively. This result suggests that the cases withoutthe unique symptoms may have been misdiagnosed as common cold or other febrile illnesses.One hundred and fifty-four suspected cases were not scrub typhus cases by the serological tests. Thethree major clinical symptoms were present in approximately a half of these negative cases, escharbeing observed in approximately 70%. This may suggest the presence of new type of scrub typhuscan not be diagnosed by the present laboratory tests. Clinical features of scrub typhus in Japan werewell revealed, and information obtained in the present study is useful for improving clinical diagnosis.It should, however, be stressed that there were cases that could not be correctly diagnosed only bythe clinical symptoms, suggesting that it is important to improve the serological tests.