Naturally-occurring toxoplasma infection has been observed for years in various kinds of wild animals. However, the infection situation has not been well characterized due to a lack of research. In present study, latex fixation tests were conducted for 109 main-land raccoon dogs (67 males and 42 females) all of which were kept in Kanazawa Zoo in Yokohama City, Kanagawa Prefecture between 1991-1994 to measure levels of toxoplasma antibodies. The test results indicated 20 positive samples out of the total 109, an 18.3% positive rate. This demonstrates that toxoplasma infection exists in the raccoon dog population in Kanagawa Prefecture, and that the raccoon dog could be a source of spread of toxoplasma infection. We believe there is significant reason to continue the investigation as a part of a prophylaxis for zoonotic diseases.