The intestines and hearts of dogs were examined for Toxocara canis, Toxascaris leonina, and Dirofilaria immitis, after necropsy between June 26 and September 29, 2004 in Chuncheon, Korea. Of the 662 dogs examined, 6 were infected with T. canis $(0.9\%),;86;with;T.;leonina;(13.0\%)$. Fifty dogs were infected with D. immitis among 500 dogs examined $(10.0\%)$. Five were co-infected with T. canis and T. leonina, and three were co-infected with T. leonina and D. immitis. The cumulative positive infection rate for three species was $134/662(20.2\%)$. Considering previously reported seropositive rates of T. canis excretory-secretory antigen, i.e., $5\%$ in the adult population in Korea, the possibility of toxocariasis caused by T. leonina should be reevaluated.