The importance of antimicrobial resistance and the urgent need to combat it has increased the already existent complexity of licensing and approval of antimicrobial agents for use in animals due to its possible impact on animal and public health. VICH-the International Cooperation on Harmonisation of Technical Requirements for Registration of Veterinary Medicinal Products-is the trilateral (European Union-Japan-United States) program that has the goal of harmonizing technical requirements for veterinary product registration. This article aims to describe the data requirements and testing necessary to build a registration file to obtain marketing authorization for a new antimicrobial agent for use in animals. This information is needed in the context of the risk assessment framework currently used in the approval of veterinary medicinal products containing antimicrobial substances. This framework considers the consequences of the uncontrolled quality of the antimicrobial product, the direct exposure of people to the antimicrobial product (human occupational safety and consumer safety), inadvertent exposure of organisms to the antimicrobial product (environmental safety), the antimicrobial product causing harm in the treated animals (target animal safety), and failure to achieve claims (efficacy). Approved veterinary medicines need to have a clear positive benefit associated with their use because of the risk to public health, animal health, and the environment. However, the presence of antimicrobials in the environment exerts a selective pressure for resistance genes in bacteria, and there is growing worldwide concern about the role of polluted soil and water environments in spreading antimicrobial resistance and the role of the contaminant resistome due to food-producing animal antimicrobial treatment. Additionally, the international developments regarding the categorization of critically important antimicrobials with the possible restrictions of use and the monitoring and surveillance of antimicrobial resistance in animals are reviewed.