PURPOSE OF REVIEW: Refractory dyspnea is a common and distressing symptom complicating respiratory illness, including chronic obstructive pulmonary disease, and life-limiting illnesses in general, including cancer. Oxygen is often prescribed for relief of dyspnea and several consensus guidelines support this practice. The goal of this review is to outline the evidence for the use of oxygen for relief of dyspnea, with specific attention to situations in which oxygen is not already funded through long-term oxygen treatment guidelines (i.e., when PaO2 is >/=55 mmHg; also known as palliative oxygen). RECENT FINDINGS: Several recent systematic reviews, two focusing on people with chronic obstructive pulmonary disease and the other focusing on people with cancer, strengthen the evidence base behind the use of palliative oxygen for relief of refractory dyspnea, and support the observation that there are subgroups of people who benefit from oxygen, such as individuals with chronic obstructive pulmonary disease. SUMMARY: The data highlighted in this review support the belief that certain individuals benefit from the use of palliative oxygen but continue to suggest that definitive randomized trials are required to fully establish the benefit of palliative oxygen and to delineate characteristics predictive of benefit.