The study of human genetic diseases can be greatly aided by animal models because of their similarity to humans in terms of genetics. In addition to understand diverse aspects of basic biology, model organisms are extensively used in applied research in agriculture, industry, and also in medicine, where they are used to model and understand disease and to test new systems of treating disease. The range of model organisms is large, extending from microbes to primates. Mice are widely considered to be the prime model of genetic human disease. In this review, we will mainly focus on the mouse, which is the mammalian species with the best studied genetics.Key words: Animal models, mice, genetic diseases