The increase of commerce between developing countries requires a harmonised system for accepting the results of clinical trials (CT) of veterinary products, similar to those that exist in developed countries. The objective of this paper is to propose a basis for the creation of a system that harmonises CTs for approving veterinary products (VP) for registration. Such a system would be a step towards unifying the CTs of different countries, while maintaining country-specific variations that are compatible with the scientific method, international standards, and the principles of objectivity, transparency and confidentiality. Basic requirements to be fulfilled by both private institutions and public offices are described, as are professional responsibilities and possible administrative procedures that could be adapted in each country. The conclusion reached is that a harmonised system is feasible, as has been demonstrated in numerous countries throughout the world. A harmonised system will result in a more efficient product approval process, a reduction in costs, greater transparency in controls, an improvement in the reliability of the health system, and a reduction in the time the process takes. It will also contribute to animal welfare by avoiding the need to repeat trials. The author acknowledges that there are cultural, technological and economic limitations and that these problems, and others, have yet to be overcome.