Genetically modified animals are a widely used tool in biomedical research, since it allows modeling diseases, studying their pathological conditions and identifying and validating new drugs. One of the most common diseases studied in recent years is metabolic disorders resulting from abnormalities in enzyme systems involved in the intermediary metabolism of living organisms with a heavy impact on society. To understand the physiological mechanisms underlying these disorders, animal models, currently the transgenic type, have been employed. It is important to emphasize that there are various metabolic disorders that are not only congenital but can be acquired or a coexistence of both types. The aim of this chapter, therefore, is to describe the most commonly used rodent models focusing mainly on global emerging pathologies, obesity, diabetes and metabolic syndrome.