The aim of this study was to identify and determine the prevalence of Eimeria species affecting sheep raised extensively in a semiarid region of Brazil. Fecal samples of native sheep were collected during the rainy and dry seasons. The degree of infection was determined by counting oocysts per gram (OPG) of feces, and the morphometric method was used for species identification. Oocysts were found in all the properties assessed, in which 68.3% of the animals were infected. The prevalence of oocysts was influenced by the season and animal category (P<0.05). It was higher during the rainy season than the dry season (80.2% vs. 55.8%) and highest in young animals than the adults animals (68.2% vs. 39.6%). The OPG was lower during the dry season (1,269 ± 312 vs. 4,400 ± 1,122). Ten species were found; of these, E. ovinoidalis, E. granulosa, E. faurei, and E. crandallis were the most frequent. E. ovinoidalis and E. crandallis were found in all properties, with their prevalences being 19.4% and 13.6% respectively. The high prevalence of pathogenic species shows that eimeriosis is a risk for animals raised extensively in the semiarid region.