To determine the seroprevalence of anti-Neospora caninum and anti-Toxoplasma gondii antibodies in
dogs in Iran and to investigate related risk factors to the infection, a study was conducted in Chaharmahal va
Bakhtiari, Isfahan and Khoozestan provinces, locate in west central parts of Iran. For this, 548 serum samples were collected from dogs during an 18 month period from July 2007 to February 2009. Serodiagnosis of N. caninum was carried out using a homemade indirect ELISA test and of T. gondii using an optimized indirect ELISA designed using an affinity purified 30 kDa T. gondii surface antigen (SAG1). From a total of 548 dogs, 159 (29%) were positive for N. caninum and 147 (26.8) for T. gondii. 49 (8.94%) dogs had detectable antibodies against both N. caninum and T. gondii. No sex predisposition was detected in the examined animals, but age and living places were of high importance for both N. caninum and T. gondii infections.