Omissions and errors are commonly found concerning hospital oxygen use and the use of nebulizers. The aim of the study was to record oxygen use in seven hospitals located in a large district city of Greece. Another aim was to record the use of nebulizers in the same hospitals. We included 105 head nurses (HNs) working in seven hospitals of a large city district of Greece. Data were collected after interviewing each HN using a questionnaire and completing an anonymous data form. Data are expressed as percentages and analyzed using the chi-square test. We found that 41% of HN believed O(2) is a gas that improves patient's dyspnea. The majority of the nurses (88.6%) stated that there was no protocol for O(2) therapy in the departments in which they worked. We found that O(2) therapy was commonly started, modified, discontinued by nurses in the absence of a medical order. Oxygen therapy was commonly not guided by arterial blood gas (ABG) analysis. We also found that there are no guidelines to prevent O(2) therapy interruption during intra-hospital transportation, and that few measures were taken to prevent O(2) explosion. In 95.2% of the departments the nebulizers were filled with tap water and were not changed on a daily basis (81.2%). Our results indicate that educational programmes, nursing protocols and guidelines are becoming mandatory in our country in order to ensure the proper use of O(2) therapy and nebulizers.