Belly breathing, a type of deep diaphragmatic breathing that typically produces a relaxed state, is a popular behavioural intervention used to reduce anxiety in children undergoing medical procedures. Studies have shown that decreased anxiety is not only associated with decreased distress but also with decreased pain and less negative attitudes towards future medical procedures. Biofeedback is a tool that is used to teach children about the connection between mind and body. Very little research currently exists on using biofeedback applications to teach relaxation to children in a clinical setting; however, some evidence suggests that it could be effective. This study will examine the efficacy of using such a tool to teach belly breathing to children in order to reduce procedural anxiety and pain.