Abstract: "Combimed immunodeficient beige/nude mice were developed on the beige and nude parents with the same C 57 BL/6 J genetic background through cross-intercross mating systm. This animal model is the first report in China, The assay for NK-cell cytotoxicity and lymphocyte proliferation showed a significent deletion of the function of T- and NK- cells in the beige-nude mouse. Beige gene has an effect on melanin synthesis, the color of external ear and iris of this genotype mouse became pale and clearly different from another ones which is dark grey. It makes simpler to distinguish the beige-nude mouse in the progressive breeding. Experiment demonstrated beige-nude mouse is a valuable animal model in immunology and tumor metastasis research. In this report, the interaction between bg-gene and nu-gene were discussed."