Transgenic plants present enormous potential as one of the most cost-effective and safe systems for large-scale production of proteins for industrial, pharmaceutical, veterinary and agricultural uses. Heat-stable plant-derived vaccines that are administered orally could, in effect, enhance vaccine coverage in children and infants, particularly in the Third World. Infantile diarrhea and other enteral pathologies are leading causes of morbidity and mortality in developing countries. Plant-made vaccines have the potential to enhance vaccine coverage in children and infants, particularly in resource-poor regions. Plant-based vaccines delivered orally are well suited for combating gastrointestinal diseases, and this has been the focus of a number of Phase 1 clinical trials. A significant hurdle impacting protein delivery to the intestinal immune system stems from the fact that many antigens are rapidly degraded within the harsh environment of the digestive tract. Plant-made vaccines offer an advantage as plant cells provide protection and prevent degradation of the antigen as it passes through the gut. This review attempts to describe the current status of plant-derived vaccines and their potential to champion the battle against infectious diseases in poorly developed countries.