The aim of this study was to investigate the physiological responses of long-term hospitalized children when exposed to live music. Twenty-one paediatric patients at Great Ormond Street Children's Hospital, London, between 3 months and 14 years of age, took part in the study. They were all long-term patients with cardiac and/or respiratory problems. They received music sessions for about 30 minutes, according to the child's state, during which a musician sang and played guitar. The children's physiological responses were measured with a pulse oximeter and their oxygen saturation level as well as their heart rate recorded before and after the music session. The analysis of the data showed that during the music sessions, the children's heart rate did not change significantly. However, when their oxygen saturation level was examined, a different picture emerged. In fact, the percentage of oxygen present in the blood increased significantly by the end of the music session. This suggests that music has an effect on the state of paediatric patients, potentially improving their physiological and psychological well-being. (Contains 2 figures, 1 table and 1 note.)