Cancer in a pediatric population represents the majority of non-related to trauma deaths. In most developed and emerging countries there is a need for early and accurate imaging detection, usually with fast examinations protocols, and no or low radiation exposure to avoid a secondary radiation induced neoplasia. The advance of magnetic resonance imaging techniques permitting the use of whole body images on oncology patients and multifocal diseases and the use of diffusion weight images DWI techniques allow additional metabolic information for WB-MRI with growing evidence that the disease metabolic activity is correlated with cellularity in some tumors. This permits DWI sequences and suggests tumor activity with the therapy response as an alternative to PET-CT. WB-MRI has proved to be more sensitive than scintigraphy in detecting both marrow and non-marrow involvement on lymphoma patients and can be a very good alternative to those who cannot undergo a PET-CT. Other small cell neoplasms such as Ewing family, neuroblastoma and some sarcomas also have been effective evaluated by WB-MRI. On palliative care patients, WB-MRI plays a rule on detecting lesions that can cause pain or pressure over vital structures. In conclusion, WB-MRI has been proved an extremely useful method on multifocal diseases and oncology with the same routine MR contraindications and should be, respecting the limitations inherent to any radiology method, accepted as another powerful tool especially in pediatric oncology. It can be used to avoid radiation exposure related disease and could be more available to these patients.