Portable oxygen therapy is a major challenge for patients and clinicians. Additionally, the available evidence on this subject is poor considering that only a few studies have been published and the results have not been encouraging. We explored the current trends, habits and beliefs among patients receiving portable oxygen therapy in a geographical area of Madrid, Spain (4 051 862 inhabitants). A telephone-based survey was conducted among patients selected from a database who were undergoing portable oxygen therapy. The number of patients on home respiratory therapies on December 31, 2017 was 81 559 (prevalence 2013.30 per 100 000 inhabitants). A total of 19 492 patients were on home oxygen therapy (HOT) (prevalence 481.16 per 100 000 inhabitants). Of these, 4015 patients (20% of the total of patients on HOT) received ambulatory oxygen therapy. In the analysed period, 1942 patients were selected (57.31% male and 42.69% female). The mean±sd age was 73.89±11.67 years. Most of patients had portable oxygen concentrators (99.59%). The survey was completed by 1777 patients. Most of patients thought they had been prescribed HOT for respiratory failure. 55% of the participants surveyed reported having carried out a walking test with oxygen to know the amount of oxygen they needed. 71% of the participants reported leaving the home for between 1 and 3 h a day. Most of them were carrying portable devices in a wheeled cart (51.94%). Our study data obtained from a large sample of oxygen-dependent individuals provide valuable information regarding domiciliary and portable oxygen usage in Madrid.