A recent report that aminoglycoside antibiotics restored the expression of functional dystrophin to skeletal muscles of mdx mice, a model of Duchenne muscular dystrophy (DMD), raised hopes that DMD may be treatable by a conventional drug. Subsequently, several human trials were initiated for evaluating gentamicin therapy in selected DMD patients. An increase of dystrophin expression was not detected in one human trial that was fully reported. Here, we report that we were unable to replicate previously published beneficial results by gentamicin treatment in the mdx mouse. Therefore, we believe that additional animal experimentation is required to further evaluate the possibility of in vivo aminoglycoside therapy of DMD.