In many low- and middle-income countries, hundreds of thousands of people—including many newborns, children, and pregnant women—die needlessly each year from hypoxemia, or a low concentration of oxygen in the blood. Hypoxemia can be caused by a range of illnesses and complications, including pneumonia, neonatal infections, premature birth, obstetric emergencies, and respiratory infections like COVID-19.The COVID-19 pandemic has pointedly highlighted the lack of access to oxygen in lower-resource settings. The biggest barriers to oxygen therapy access include inadequate supply and human resource capacity, funding constraints, and the inability to deploy resources in countries rapidly in a way that ensures maximum impact while not overwhelming existing health care systems. The oxygen landscape is at a pivotal point where short-term pandemic-response efforts require continued support while transitioning to long-term, sustained strategies for ensuring access.This fact sheet offers an overview of the SOURCE project to support countries to equitably improve access to high-quality oxygen services at all levels of the health care system in order to reduce maternal, child, and overall mortality from hypoxemia-related causes. To do so, PATH will incorporate near-term pandemic-response work into a robust set of implementation, advocacy, and research activities that will ensure long-term access to medical oxygen and resilient systems for future pandemic-response efforts.