Abstract: Neospora caninum an obligate intracellular protozoan parasite is recognized as a major cause of abortion in cattle while limited information is presently available on the seroprevalence of Neospora antibodies in horses worldwide. The aim of the present study was to determine serologic prevalence of Neospora infection in horses in East-Azerbaijan province of Iran. Sera from 100 horses from Tabriz city in East-Azerbaijan province, Northwest Iran were examined for antibodies to Neospora sp. using Neospora Modified direct Agglutination Test (N-MAT). Antibodies to this parasite were detected in 28 (28%) of the examined serum samples. About 32% of the samples had titer of 1:40 while then reduced to 28% when 1:80 serum dilution was applied as significant cut off titer. This study is the first investigation carried out on the Neospora in horses in East-Azerbaijan province of Iran and indicates that horses in Iran are exposed to this parasite.