Whole-body MRI (WB-MRI) has emerged as a valuable tool for comprehensive head-to-toe evaluation of various pediatric systemic disorders. The unique ability of whole-body imaging combined with lack of ionizing radiation make it an attractive option for staging and follow-up of malignancies as well. There is, however, the challenge of long acquisition time, which requires that protocols be tightly tailored as per patient age and the expectation from the examination. In this chapter, we aim to summarize the available evidence on current practices in whole-body MRI in pediatric oncology. The discussion is divided into two parts, diagnostic applications in children with multisite tumor involvement such as lymphoma or neuroblastoma and screening applications in children with no known malignancy but cancer predisposition syndromes.