BACKGROUND: Although reductions in bone mineral density are well documented among children during treatment for cancer and among childhood cancer survivors, little is known about the long-term risk of fracture. The objective of this study was to ascertain the prevalence of and risk factors for fractures among individuals participating in the Childhood Cancer Survivor Study (CCSS). METHODS: Analyses included 7414 >/=5-year survivors of childhood cancer diagnosed between 1970 and 1986 who completed the 2007 CCSS follow-up questionnaire and a comparison group of 2374 siblings. Generalized linear models stratified by sex were used to compare the prevalence of reported fractures between survivors and siblings. RESULTS: The median ages at follow-up among survivors and siblings were 36.2 years (range, 21.2-58.8 years) and 38.1 years (range, 18.4-62.6 years), respectively, with a median 22.7 years of follow-up after cancer diagnosis for survivors. Approximately 35% of survivors and 39% of siblings reported >/=1 fracture during their lifetime. The prevalence of fractures was lower among survivors than among siblings, both in males (prevalence ratio, 0.87; 95% confidence interval, 0.81-0.94; P < .001) and females (prevalence ratio, 0.94; 95% confidence interval, 0.86-1.04; P = .22). In multivariable analyses, increasing age at follow-up, white race, methotrexate treatment, and balance difficulties were associated with increased prevalence of fractures among female survivors (P = .015). Among males, only smoking history and white race were associated with an increased prevalence of fracture (P < .001). CONCLUSIONS: Findings from this study indicated that the prevalence of fractures among adult survivors did not increase compared with that of siblings. Additional studies of bone health among aging female cancer survivors may be warranted. Cancer 2012. (c) 2012 American Cancer Society.