Aged sarcopenia is characterized by loss of skeletal muscle mass and strength, and mitochondrial dysregulation in skeletal myocyte is considered as a major factor. Here, we aimed to analyze the effects of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) on mitochondrial reactive oxygen species (ROS) and nuclear factor erythroid 2-related factor 2 (Nrf2) in aged skeletal muscles.