Prevalence of Eimeria species among broiler chicks in Tabriz (Northwest of Iran)Abstract : Five chicks (2?6 weeks of age) were taken randomly from each of 218 broiler farms in Tabriz northwest of Iran. These chicks were submitted for post-mortem and parasitological examinations. Five Eimeria spp. were identified: E. acervulina, E. tenella, E. necatrix, E. maxima and E. mitis. The overall prevalence of Eimeria spp. among examined farms was 55.96 % (122 of 218 farms). E. acervulina was the most prevalent species (23.58%). Prevalences did not vary by flock size. Also, neither the use of coccidiostat nor previous coccidiosis clinical outbreaks were associated with the prevalence of infestation. The prevalence of infestation increased with the age of the chickens. Chickens with 5 weeks of age showed the highest prevalence of infestation.