Domicillary long-term oxygen therapy (LTOT) is an established procedure, with demonstrable survival benefit. It is a complicated treatment modality and, for optimum cost-benefit to be attained, it must be performed well. This calls for careful patient selection and the selection of a suitable form of treatment for each individual patient. Follow-up, preferably with home care as an option, is also essential. No full cost-benefit analysis in economic terms has, so far, been presented. Even so, some suggestions can be made concerning the factors which need to be considered to obtain the best possible results.