Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 8 2 2013 06 15 234 241 EN F Arabkhazaeli Department of Pathobiology, Faculty of Veterinary Medicine, University of Tehran, Iran. M Modrisanei Department of Animal and Poultry Health and Nutrition, Faculty of Veterinary Medicine, University of Tehran,Iran S Nabian Department of Pathobiology, Faculty of Veterinary Medicine, University of Tehran, Iran B Mansoori Department of Animal and Poultry Health and Nutrition, Faculty of Veterinary Medicine, University of Tehran,Iran A Madani Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tehran, Iran 2015 10 14   Background: In this study, the presence of resistance to diclazuril, amprolium+ethopabate and salinomycin, representing some of the commonest anticoccidials in Iran’s poultry industry, against three mixed Eimeria field isolates were investigated. Methods: Three Eimeria field isolates, collected from typical broiler farms in Iran, were propagated once, inoculated to 480 broilers, comprising 30 chicks in each treatment. The non-medicated or medicated diets containing one of the above mentioned anticoccidials were provided ad-lib. Drug ef-ficacy was determined using the Global index (GI), Anticoccidial Sensitivity Test (AST) and Opti-mum Anticoccidial Activity (OAA). Results: None of the field isolates were fully sensitive to the selected anticoccidials. All isolates showed reduced sensitivity/partial resistance to salinomycin. Resistance to amprolium+ethopabate was evident and partial to complete resistance was recorded for diclazuril. Conclusion: Limited efficacy of the selected anticoccidials is obvious. Considering the cost of conti-nuous use of anticoccidials in the field, altering the prevention strategy and rotation of the anticocci-dials with better efficacy, would prevent further economic losses induced by coccidiosis. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/500 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/500/444