The success of treatment for children with cancer has resulted in a growing population of adult survivors, yet these individuals may be at risk of serious long-term health problems as a result of the treatment they have received. This study explores the pattern of morbidity within a population of 290 adult survivors of cancer in childhood assessed at a median of over 15 years from diagnosis. Acute lymphoblastic leukaemia (33%) and Hodgkin's disease (15%) were the most common primary diagnoses represented. 85% of the whole group had received treatment with chemotherapy, 81% with radiotherapy, 48% with significant surgery and 28% with all three modalities. Overall, 58% of the survivors had at least one 'chronic medical problem' and 32%, two or more. Infertility (14%), nephrectomy (11%), thyroid hormone deficiency (9%), visual handicap (9%), sex hormone (7%) and growth hormone (7%) replacement therapy were the most common problems. Compliance with long term follow-up was good and an audit of an unselected sub group of all the survivors in the study showed that 84% had attended for surveillance over a period of 1 year, accounting for 222 visits of follow up clinics: 15% were also attending other specialist follow-up including psychiatry, orthopaedic, endocrine, dental and cardiac clinics. In conclusion, survivors of cancer in childhood experience actual or potential threats to future health. More than half have at least one chronic medical problem and demonstrate a significant use of medical resources. These data support the need for the continuing follow-up of survivors of cancer in childhood into adult life and the provision of the resources to do so. Optimal patterns of care and future approaches to the reduction of sequelae in future generations of survivors are discussed.