Viruses which infect the gastrointestinal tract are well suited for examining the immune response(s) to oral delivery of antigen and exploring the advantages and pitfalls of oral vaccines. We have used recombinant DNA techniques to produce nonreplicating self-assembled virus-like particles (VLPs) from two gastrointestinal viruses, rotavirus and Norwalk virus. Both of these viruses normally cause acute gastroenteritis in man or animals. The VLPs are morphologically and antigenically similar to the native virus and quite stable, features which are advantageous for their use as subunit vaccines. In addition, these VLPs could be useful as carriers of foreign epitopes from heterologous pathogens or of drugs which need to be delivered to the gastrointestinal track. This paper briefly reviews the properties of these VLPs made in insect cells and data showing their potential as subunit vaccines for parenteral or oral delivery.