Animal research on the Space Station presents the need for bioisolation, which is here defined as instrumental and operational provisions, which will prevent the exchange of particles greater than 0.3 μ size and microorganisms between crew and animals. Current design principles for the Biological Research Project thus call for: 1. use of specific pathogen-free animals; 2. keeping animals at all times in enclosed habitats, provided with microbial filters and a waste collection system; 3. placing habitats in a holding rack, centrifuge, and workbench, all equipped with particulate and odor filters, 4. washing dirty cage units in an equipment cleaner, with treatment and recycling of the water; 5. designing components and facilities so as to ensure maximal accessibility for cleaning; 6. defining suitable operational procedures. Limited ground tests of prototype components indicate that proper bioisolation can thus be achieved.