Dystrophin-deficient dogs, as canine replicas of DMD patients, represent the choice model to evaluate systemic therapeutic strategies. In this context, the development of a quantitative, discriminating and non-invasive method of gait quality assessment is essential. Accelerometry, a technique based on 3D recording of accelerations, is the method we have chosen to develop, because it seems to be easy to perform in dogs and a source of several quantified parameters. In this aim, dystrophic and healthy dogs were encouraged to walk as spontaneously as possible along a 20 m corridor, and timed over 5 m. Three axial accelerations were recorded close to the center of gravity, the accelerometer being placed under the sternum, using a light elastic belt tightened around the thorax (Equimetrix device ®). Recorded data were analysed using specific gait analysis software on ten seconds-samples of steady state locomotion. Eleven dystrophic and 7 healthy adult dogs were used to validate parameters able to discriminate these two groups. The mean regularity of dorso-ventral accelerations was found to be significantly higher in healthy than in dystrophic dogs. The frequency and length of strides were considerably reduced in dystrophic dogs, as well as the total mechanical power of gait (W/kg). Interestingly, the medio-lateral component of the power was significantly increased in dystrophic animals, demonstrating a swaying component in the gait of these dogs. Longitudinal studies in puppies show that the total power of gait is early reduced at 2 months of age in dystrophic animals, whereas the increase of the medio-lateral component of the power and the decrease of regularity progressively occur with age. These results validate accelerometry as a useful tool of functional evaluation of dystrophic dogs, since it is simple, non-invasive and efficient to quantitatively discriminate them from healthy dogs. Moreover, they provide reference data on healthy and untreated dystrophic dogs at different ages, representing comparison points for dogs receiving systemic treatments.