This thesis investigates the adverse outcomes amongst survivors of childhood cancer using the British Childhood Cancer Survivor Study (BCCSS) and the Pancare Childhood and Adolescent Cancer Survivor Care and Follow-up studies (PCSF). The specific aims were to investigate (1) adverse outcomes up to 50 years of follow-up in survivors of Wilms’ tumour; (2) risks of hospitalisations due to renal morbidities in childhood cancer survivors; (3) risk of subsequent primary neoplasms arising in the digestive system in survivors of childhood cancer; and (4) adverse outcomes beyond 50 years of follow-up in survivors of heritable retinoblastoma. This thesis demonstrated that survivors of Wilms’ tumour are at substantial risk of premature mortality, particularly for those who have survived 30 years from original diagnosis. This particular group of survivors have the highest risk of hospitalisations due to renal morbidities, such as chronic renal failure, and subsequent primary neoplasms in specific organs in the lower digestive system. Survivors of heritable retinoblastoma who received external beam radiotherapy experienced an increased risk of subsequent primary neoplasms developing above the shoulder, whereas those who received brachytherapy were similar to those who did not receive any radiotherapy and did not experience an increased risk of subsequent primary neoplasms.