We report two cases of tsutsugamushi disease which occurred in the spring of 1998. One patient presented with fever, rash, lymphadenopathy and eschar. He was exposed to bush areas on March 29, 1998 and developed symptoms starting April 6, 1998. The other patient visited our hospital because of fever, headache, and vomiting which developed since May 21, 1998. Physical examination revealed rash, lymphadenopathy, and eschar. Cerebrospinal fluid was positive for Orientia tsutsugamushi by using polymerase chain reaction. Most tsutsugamushi cases occur between October and December in Korea. The seasonal variation in the incidence of tsutsugamushi disease is probably related to the life cycle of the vector mite. The frequency of Leptotrombidium pallidum, a major vector mite in Korea, shows a large peak in autumn and a smaller peak in spring. Our cases confirm that tsutsugamushi disease can occur in the spring in Korea.