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Magnetic resonance imaging (MRI) is not the initial imaging technique in pediatric abdominal neoplasms, but it is an excellent method to assess tumor extension due to superb soft-tissue contrast. The main disadvantage is time-consuming procedure that frequently warrants general anesthesia in children. Novel CT machines provide excellent images of the body (e.g. lung parenchyma) with significantly reduced radiation burden, mostly without general anesthesia. Here we present typical pediatric abdominal tumors where MRI is inevitable part of treatment planning. With neuroblastoma MRI can accurately assess potential invasion of the spinal canal and bone marrow, which is beyond the scope of ultrasound. MRI is optimal modality to evaluate therapeutic response and detect residual or recurrent disease. It reliably reveals tumor necrosis, hemorrhage, and cystic degeneration, but cannot detect calcifications within the tumor tissue (e.g. neuroblastoma). Due to its capacity to comprehensively assess liver parenchyma, vascular and biliary structures, MRI is the method of choice to evaluate resectability of liver neoplasms. MR reliably reveals tumor invasion into the paravertebral soft tissues and neural structures of the spinal canal. Beyond morphology, MRI obtain functional information from the tissue when diffusion weighted imaging (DWI), dynamic contrast-enhanced MRI (DCE-MRI) or MR spectroscopy are applied. For example, high cellular tumor tissue or abscess will cause restriction of water diffusion which can be quantified. Increase of water diffusion corresponds to decrease in cellularity indicating favorable response to chemotherapy. Furthermore, using DWI we can guide biopsy needle to the most cellular part of the tumor to obtain representative sample. [ABSTRACT FROM AUTHOR]