Long term oxygen therapy (LTOT) is the provision of oxygen therapy to a patient at home for at least 15 hours a day, usually for the duration of the individual’s life. It is very important for GP trainees to proactively seek patients who meet the criteria for LTOT as many patients would gain survival benefit from home oxygen therapy but do not receive it. This article will outline the assessment of patients with chronic hypoxaemia and the investigations required to determine suitability for LTOT before referral to secondary care. It will also cover the process of delivery and monitoring of home oxygen within the UK, outlining the differing oxygen sources and delivery devices available. The article includes an overview of the professional bodies involved in organising home oxygen, especially the fire service in undertaking risk assessment. A section on palliative oxygen therapy is included as this is an area in which instigation and monitoring of home oxygen will often be organised solely by the GP.