Mortality occurred in Japanese crucian carp Carassius cuvieri in a reservoir in Chungnam Province, Korea, in March 2002. Moribund fish showed severe anemia in the gills and piscicolid leeches that were identified as Trachelobdella sp. were reported as the cause of the mortality. Re-examination of the preserved leech specimens reveals that they are not Trachelobdella sp. but Limnotrachelobdella sinensis. The external morphology of the specimens is described. This finding represents the second record of L. sinensis in Korea. The impact of infestation by L. sinensis on a host is discussed in relation to fish mortality.