As the major interface with the environment, the skin encounters a steady array of injuries and incursions of foreign materials and pathogens. In response to these continuous challenges, an effective system of cutaneous immunity has evolved to defend the skin against pathogens, to expel foreign materials and to facilitate the repair process. The detection of foreign antigen within tissue initiates a series of reactions that result in a concerted set of physiological changes. Inflammation is the most outwardly evident of these changes. In the normal course of events inflammation serves to protect the organism and initiate the repair of damaged tissue; however, in numerous different circumstances inappropriate inflammation can itself be pathological. The imperative to understand and develop means to control pathological inflammation of skin has led to the study of animals with cutaneous inflammatory disorders. Furthermore, the development of genetic engineering methods has led to the creation of a number of strains of mice in which improper expression of certain genes causes inflammatory disorders. In this chapter we will review the use of such animals to study the process of inflammation in vivo.