Concerns regarding the possibility of adverse public health impacts of antimicrobial agents have urged veterinarians, public health officials, regulatory authorities and other stakeholders to explore the risks, implementing risk management measures and searching for alternative products. The literature associated with the benefits and risks of antimicrobial agents used for performance is vast and has been accumulating for more than half a century. This chapter provides an introduction to this area, highlighting key historical findings and issues, as well as exploring future options. The administration of antimicrobials for performance purposes in modern food animal production programs actually offers a number of significant benefits. The chapter briefly summarizes the products used in the feed or through systemic administration. Improvements in animal husbandry, genetics and nutrition also have a profound and positive impact on animal production and health.