Long-term oxygen therapy (LTOT) is an established treatment for patients with chronic obstructive pulmonary disease (COPD) diagnosed with hypoxemia at rest or during activity. Chronic hypoxemia is a potential mediator of loss of muscle mass and oxidative capacity in COPD. In this retrospective analysis, we sought to determine whether patients with COPD receiving LTOT have impaired muscle oxidative capacity compared to those without LTOT.