Recently, a number of chemical and drug screens using zebrafish embryos have been published. Using zebrafish dystrophin mutants, we screened a chemical library for small molecules that modulate the muscle phenotype and identified seven small molecules that influence muscle pathology in dystrophin-null zebrafish. One chemical, aminophylline, which is known to be a non-selective phosphodiesterase (PDE) inhibitor, had the greatest ability to restore normal muscle structure and to up-regulate cAMP-dependent protein kinase (PKA) in treated dystrophin deficient fish. Our methodologies, which combine drug screening with assessment of the chemical effects by genotyping and staining with anti-dystrophin, provide a powerful means to identify template structures potentially relevant to the development of novel human muscular dystrophies therapeutics.