BACKGROUND: Young adult survivors of childhood cancer have an increased risk for treatment-related morbidity and mortality. In this study, the authors assessed how treatment for childhood cancer affects older-adult health and health practices. METHODS: One hundred seven adults treated for childhood cancer between 1947 and 1968, known to have survived past age 50 years, were identified from a single-institution cohort established in 1975. Updated vital status on eligible cases was obtained from public records. Survivors and a control group of their age-matched siblings and cousins completed a mailed survey to assess physical and social function, healthcare practices, and the prevalence of common adult illnesses. RESULTS: Of the 107 survivors known to be alive at age 50 years, 16 were deceased at follow-up; 7 deaths could be associated with prior treatment (second malignancy in radiation field [3], small bowel obstruction after abdominal radiation [2], and cardiac disease after chest irradiation [2]). The 55 survivors (median age, 56 years; range, 51-71 years), and 32 family controls (median age, 58 years; range, 48-70 years), reported similar health practices, health-related quality of life, and social function. However, survivors reported more frequent visits to healthcare providers (P < .05), more physical impairments (P < .05), fatigue (P ¼.02), hypertension (P ¼.001), and coronary artery disease (P ¼.01). An increased risk of hypertension was associated with nephrectomy during childhood (odds ratio, 18.9; 95% confidence interval, 3.0-118.8). CONCLUSIONS: The oldest adult survivors of childhood cancer continue to be at risk for treatment-related complications that potentially decrease their life expectancy and compromise their quality of life. Cancer 2010;116:497-505.