Present-day coccidiosis control aims at the reduction of the numbers of parasites in the environment to levels which will not cause pathogenic effects in the host. The methods used will depend upon the species of Eimeria concerned, and the system of management. Adequate disinfection is essential and research should be directed towards the development of active products, which are easy to use, and the establishment of standard methods for testing their efficacy. Good hygiene slows down the spread of organisms and, in certain cases, this alone will give sufficient control. Immunisation of the host would increase the numbers of oocysts necessary to cause pathogenic effects. This method of control would only be applicable to the rearing of pullets and seems to be possible only by chemotherapeutic treatment a few days after withdrawal of drug at preventive concentrations. Of the methods of chemoprevention available (complementary treatment, rotation, association and rapid alternation), rapid alternation (shuttle and dual programmes) is the one most likely to reduce failure due to the development of drug resistance.