Growing fiscal deficits and greater awareness of the huge economic cost of often-inefficient government activities have renewed interest in transferring the delivery of important services from the public to the private sector in developing countries. This article, drawn from a longer study, offers a framework for determining the appropriate roles of the public and private sectors in delivering animal health services, such as veterinary surveillance, disease vector control, vaccination, clinical treatment of sick animals, inspection of livestock products, and veterinary research and extension. The profitability and therefore the supply of private veterinary services is governed by several factors arising from economies of scale, such as the size of the livestock enterprises in the locality, the nature of potential or actual diseases, and the types of animals raised in the production systems. Thus, in areas where private veterinary work is unprofitable or where other types of market failure occur, economic or social concerns may make some type of public intervention necessary. The transfer of animal health services from the public to the private sector must be done selectively, and government support may be needed to ensure the success of such transfers.