Muscle dysfunction often occurs in patients with chronic obstructive pulmonary diseases (COPD) and affects ventilatory and non-ventilatory skeletal muscles. We have previously reported that hypercapnia (elevated CO 2 levels) causes muscle atrophy through the activation of the AMPKα2-FoxO3a-MuRF1 pathway. In the present study, we investigated the effect of normoxic hypercapnia on skeletal muscle regeneration. We found that mouse C2C12 myoblasts exposed to elevated CO 2 levels had decreased fusion index compared to myoblasts exposed to normal CO 2. Metabolic analyses of C2C12 myoblasts exposed to high CO 2 showed increased oxidative phosphorylation due to increased fatty acid oxidation. We utilized the cardiotoxin-induced muscle injury model in mice exposed to normoxia and 10% CO 2 for 21 days and observed that muscle regeneration was delayed. High CO 2-delayed differentiation in both mouse C2C12 myoblasts and skeletal muscle after injury and was restored to control levels when cells or mice were treated with a carnitine palmitoyltransfearse-1 (CPT1) inhibitor. Taken together, our data suggest that hypercapnia leads to changes in the metabolic activity of skeletal muscle cells, which results in impaired muscle regeneration and recovery after injury.