CNS tumours are the most common solid tumour in paediatrics and the most common cause of childhood cancer deaths. The diagnostic role of Diffusion Tensor Imaging (DTI) in patients with either medulloblastoma (MB), pilocytic astrocytoma (PA) or ependymoma (EP) was investigated. Fractional anisotropy (FA) and mean diffusivity (MD) means were found to be significantly different between tumour groups, as determined by one-way ANOVA (p=0.0002 and <0.0001). MD distributions enabled classification of tumour type, using linear discriminant analysis (LDA), with an average accuracy of 80%. DTI metrics were shown to provide an insight into the structure of paediatrics CNS tumours with LDA classification using MD demonstrating improved accuracy over FA.