In Korea 8 tsutsugamushi disease patients were reported among the United Nations Forces personnel during 1951-54, but the disease was not known among the native Koreans. In Chinhae, patients with fever, chills, headache and rash were observed in every late autumn to early winter for many years, but etiologic diagnosis was not made. In 1985, there were 34 such patients. The authors were able to determine the disease as tsutsugamushi disease by observing the pathognomic eschar in 4 patients and demonstrating antibodies against Proteus OXK and Rickettsia tsutsugamushi antigens in 21 patients. The patients were mostly females of over 30 years of age. It was considered that most of them contracted the infection while doing farm works or picnic at the outskirts of Chinhae city and the adjacent areas. They were treated with chloramphenicol and no fatalities were observed.