Lyme disease is an infecious disease caused by Borrelia burgdorfieii and has been reported world-wide. The spirochete invades multiple organs and induces manifesations in the skin, joints, neri us and cardiovascular systems. 13espite a considerable amount of serological evidence and isolation of R burgdorferi in ticks, no human case has yet been reported in korea. In this report, we present the first clinical case of Lyme disease in Korea. A female patient, 26 years old, developed clinical signs of eryth m,i chronicum migpans about ten days after traveling to a rural area and responded well to treatment ith entibiotions. Laboratory tests showed elevated IgM and IgG responses to B. burgdorferi, and a spirociete was found in a skin biopsy by electron microscopy. (Kor,J Dermatol 1993;31(4):601-605)