This qualitative study explored the experience and the needs for support of pediatric nurses caring for children with a mental health disorder hospitalized in non-psychiatric units in a health organization in Canada. Semi-structured interviews were conducted with 17 nurses. Content analysis revealed two main themes: (a) nurses are challenged by the lack of knowledge, the gap between access to mental health resources and the basic role of only ensuring safety. Amidst these barriers, nurses revealed their feelings of helplessness, frustration and injustice. (b) All participants voiced their willingness to break this powerlessness loop. They identified several strategies to support them: more training in mental health, better collaboration with the mental health team, etc. Further research is needed to evaluate the efficiency of these strategies to improve the delivery of care for children with a mental health disorder hospitalized in non-psychiatric units.