The diagnostic imaging procedures now available for the identification of tumours are many. Much of the information gained from one imaging procedure is simply duplicated by another without the addition of new information. This is wasteful of resources. An understanding of the advantages and limitations of each technique is essential for the selection of the best diagnostic pathways. These are briefly described and followed by a brief discussion of the role of radiology in the protocols for the treatment of childhood cancer. No attempt is made to indicate how each specific tumour should be investigated.