BACKGROUND: Paediatric hospitals are concerned with both the physical and social well-being of their young patients. These institutions often provide play and music therapy to enhance the child’s sense of normality. The purpose of this study was to test whether children in a hospital were happier during music rather than play therapy. METHODS: Sixty children were observed either during play or music therapy. Happiness was operationally defined as the frequency of smiles during a 3 minute period. RESULTS: The results showed that music therapy (M = 12.43, SD = 4.83) led to significantly more smiles than did play therapy (M = 5.83, SD = 3.10). CONCLUSIONS: Increasing the amount of time hospitals provide music therapy for child patients may be a way to increase positive effect and ultimately to increase mental and physical well-being in hospitalized children.