The first spontaneous animal model of autoimmunitywas the New Zealand black mouse, discovered in 1959. Interestingly, although several models of induced autoimmunity were demonstrated in a variety of rodents, the recognition of autoimmune disease in dogs came somewhat later. Dog breeding and selection of traits within certain dog breeds have become an important enterprise with intensive husbandry and selection criteria being applied to each breed standard. This has resulted in breeding for specific phenotypic characteristics. This selection has inadvertently led to the propagation of a number of autoimmune diseases in dogs. For example, systemic lupus erythematosus (SLE), autoimmune hemolytic anemia and thrombocytopenia, autoimmunemyasthenia gravis, and diabetes mellitus are now fairly common. In the final analysis, the appearance of autoimmunity in dogs reflects their breeding selection and illustrates the importance of genetics in the development of autoimmune disease.