Neospora caninum is a coccidian parasite of animals. It is a major pathogen for cattle and dogs and it occasionally causes clinical infections in horses, goats, sheep, and deer. Domestic dogs are the only known definitive hosts for N. caninum. It is one of the most efficiently transmitted parasite of cattle and up to 90% of cattle in some herds are infected. Transplacental transmission is considered the major route of transmission of N. caninum in cattle. Neospora caninum is a major cause of abortion in cattle in many countries. N. caninum-specific antigen is immobilized in the membrance. Another recombinant antigen is conjugated to colloidal gold. This test is aimed to the detection of anti-Neospora antibodies either in the blood specimens from dogs and cattle, horses, and so on.