Animal models of DMD have played, and will continue to play, a key role in the understanding of the pathogenesis and treatment of Duchenne muscular dystrophy (DMD). The mdx mouse and GRMD dog are spontaneous dystrophin deficient mutants and have been the most widely used models to date. A number of other murine models have been created by exposure to mutagens or genetic manipulation. The animal models have allowed the development of a number of promising experimental therapeutic approaches to DMD that are now entering clinical trial, the majority of which would not have been developed without their use. However, there has been much debate about the merits of the different animal models, which will only be finally clear as we learn from the initial human clinical trials.