Childhood cancer survivors are at risk for development of subsequent neoplasms of the CNS. Better understanding of the rates, risk factors, and outcomes of subsequent neoplasms of the CNS among survivors of childhood cancer could lead to more informed screening guidelines. Two investigators independently did a systematic search of Medline and Embase (from January, 1966, through March, 2012) for studies examining subsequent neoplasms of the CNS among survivors of childhood cancer. Articles were selected to answer three questions: what is the risk of CNS tumours after radiation to the cranium for a paediatric cancer, compared with the risk in the general population; what are the outcomes in children with subsequent neoplasms of the CNS who received CNS-directed radiation for a paediatric cancer; and, are outcomes of subsequent neoplasms different from primary neoplasms of the same histology? Our search identified 72 reports, of which 18 were included in this Review. These studies reported that childhood cancer survivors have an 8·1—52·3-times higher incidence of subsequent CNS neoplasms compared with the general population. Nearly all cancer survivors who developed a CNS neoplasm had been exposed to cranial radiation, and some studies showed a correlation between radiation dose and risk of subsequent CNS tumours. 5-year survival ranged from 0—19·5% for subsequent high-grade gliomas and 57·3—100% for meningiomas, which are similar rates to those observed in patients with primary gliomas or meningiomas. The quality of evidence was limited by variation in study design, heterogeneity of details regarding treatment and outcomes, limited follow-up, and small sample sizes. We conclude that survivors of childhood cancer who received cranial radiation therapy have an increased risk for subsequent CNS neoplasms. The current literature is insufficient to comment about the potential harms and benefits of routine screening for subsequent CNS neoplasms.