To understand the seroepidemiological patterns of epidemic typhus in Korea, a total of 2,625 patients with acute febrile episode from 1990 to 1992 were surveyed using indirect immunofluorescent antibody test (IFA). In order to increase the specificity of serology, other seven Rickettsial species were used and evaluated. As excluding the highly cross-reacted sera to other Rickettsial antigens, seropositive rate of epidemic typhus was 1.6%. Sera reactive Richettsia prowazekii cross-reacted with other Rickettsial species in the order of R. sibirica, R. akari, R. conori, Coxiella burnetii, R. typhi, Ehrlichia sennetsu, R. tsutsugamushi and R. japonica. The age distribution of seropositives with epidemic typhus generally even over 10 years old. There was no sexual and seasonal perdominance. For regional distribution, 55.5% of seropositives to R. prowazekii were residents in Seoul and Kyunggi. These results indicate that epidemic typhus might still exist in Korea. For further study and confirmation of epidemic typhus, western blot or cross-absorption test will be needed.