Isospora canis (Protozoa:Nemeseri, 1959) is an important coccidian parasite of domestic dogs. Ingestion of the sporulated oocysts causes the release of sporozoites which invade the epithe-lial lining of the intestine. Schizogony and gametogony take place in the epithelial tissue resulting in a massive proliferation of the parasite and extensive destruction of the intestinal cells (Lepp and Todd, 1974). Severe infections cause loss of appetite, diarrhea and dysentery (Levine, 1973).