A serologic survey was carried out in order to detect antibodies against Babesia ovis in a large population of Spanish ibex (Capra pyrenaica) from a hunting reserve in Catalonia, northeastern Spain. For this purpose, an indirect fluorescent antibody test (IFAT) was developed using a B. ovis isolate of ovine origin as antigen. Of the total 475 sera tested, 155 (32.6%) showed titres between 1:160 and 1:1280 and were considered positive. These results reveal that exposure of Spanish ibex to B. ovis is common in the studied area. No significant differences could be detected when comparing season or year of capture and age or sex of the animals in positive and negative samples. A high proportion of low titres was found in comparison to those reported by other researchers in sheep in Spain; this could be a consequence of the existence of some minor antigenic differences between B. ovis of domestic sheep and that found in Spanish ibex.