Coccidiosis is a complex disease that affects many farm animals, but which can be especially serious in poultry. Control of coccidiosis is essential for efficient, modern poultry productions; thus coccidiostats are extensively used to control this disease. The most commonly used coccidiostats in poultry are the polyether monocarboxylic ionophores including monensin and salinomycin. Polyether ionophores also improve feed utilization by ruminants. However, the quantity of such ionophores for effective control of coccidiosis in chickens may prove highly toxic to other agriculturally important animals. Over the past few years, we have developed monoclonal antibody‐based immunoassays for both salinomycin and monensin. In addition, we have developed immunoassays for dimetridazole and for halofuginone, the latter being a heavily used non‐ionophore coccidiostat. The advantages of the immunoassays over the conventional analytical methods are discussed as well as the characteristics of the individual immunoassays.