Glycogen storage disease (GSD) type V, also known as McArdle’s disease, is an autosomal recessive genetic disease caused by a mutation of the PYGM gene related to the synthesis of the myophosphorylase enzyme. Here, we presented the case of an 83-year-old woman who was admitted for progressively worsening weakness of her legs due to rhabdomyolysis after a COVID-19 vaccination. In the muscle biopsy, myopathy with subsarcolemmal glycogen accumulation was revealed and she was diagnosed with a mild form of GSD type V. Although COVID-19 vaccines are generally safe and encouraged for everyone, adverse events following COVID-19 vaccinations are increasing. We should pay attention to the side effects of COVID-19 vaccination including rhabdomyolysis.