RESUMEN
Anti-Neospora caninum antibodies were determined in sera of 196 water buffaloes (Bubalus bubalis) from three farms of the northern region of Brazil, using an indirect fluorescent antibody test. Antibody titers were found in 139 (70.9%) buffaloes with dilution values ranging from > or =25 to <200 in 41 animals, > or =200 to <800 in 35 animals, and > or =800 in 63 animals. The number of animals presenting titers > or =800 was statistically higher (p<0.05). All farms presented positive animals, however, the occurrence was higher (p<0.05) in farm 1 (87.2%) when compared with farm 2 (65.7%) and farm 3 (65.8%). The occurrence by age groups presented no differences (p>0.05). Results indicate a high exposure of water buffaloes to N. caninum in the Northern region of Brazil.