Results: One hundred and fifteen patients were included in the study, of whom 47.0% received oxygen without an oxygen prescription. Around 62.3% of the patients with prescriptions did not receive oxygen as prescribed. The prescriptions and oxygen administration for COVID-19 patients were better than for non-COVID-19 patients. A quarter of the patients possibly received oxygen therapy unnecessarily. Conclusion:Poor oxygen therapy practices were identified, including prescription errors, oxygen administration errors and oxygen wastage. A protocol should be developed and implemented for the prescription and administration of oxygen therapy. Training should occur to prevent oxygen wastage.Contribution: This study highlighted poor oxygen practices and prescriptions, as well as oxygen wastage in the absence of local oxygen therapy guidelines.