Play is a non-invasive, safe, and inexpensive intervention that can help children and adolescents better manage difficult aspects of hospitalisation. Play has existed in hospitals for decades but is emerging as an interdisciplinary scientific field. The field concerns all medical specialties and healthcare professionals working with children. In this review, we describe play within different clinical contexts and recommend that directed and non-directed play activities should be prioritised in future paediatric departments. We also emphasise the need for professionalisation and research in the area.