Imaging is fundamental to diagnosis and management of pediatric patients with cancer and cancer predisposition syndromes (CPSs). Whole-body MRI has emerged as a versatile tool for pediatric oncologic imaging, with the potential to spare children from ionizing radiation imparted by conventional modalities such as CT and PET. Whole-body MRI also enables simultaneous high-resolution local-regional staging and wide field-of-view distant staging in the same imaging session, with superior evaluation of the brain, spine, liver, and marrow. Recent technical advances have reduced imaging times and enhanced image quality, with continued advances on the near horizon. Pulse sequences such as whole-body diffusion-weighted imaging have also broadened the range of diagnostic information obtainable. In addition, increasing identification of children with CPSs has compelled efforts to establish surveillance imaging strategies for affected individuals, with whole-body MRI playing a pivotal role in screening algorithms for several CPSs. In light of these emerging trends, a working knowledge of oncologic whole-body MRI applications and evolving CPS surveillance algorithms is vital to providers who participate in the care of pediatric patients affected by or predisposed to cancer. Recognizing both the strengths and limitations of whole-body MRI not only enables more thoughtful implementation but also improves the accuracy of image interpretation. ©RSNA, 2019 See discussion on this article by Khanna .