The muscular dystrophies are a diverse group of genetic disorders without an effective treatment. Because they are caused by mutations in various genes, the most direct way to treat them involves correcting the underlying gene defect (ie, gene therapy). Such a gene therapy approach involves delivering a therapeutic gene cassette to essentially all the muscles of the body in a safe and efficacious manner. The authors describe gene delivery methods using vectors derived from adeno-associated virus that are showing great promise in preclinical studies for treatment of Duchenne muscular dystrophy. It is hoped that variations on these methods might be applicable for most, if not all, of the different types of muscular dystrophy.