Background: Hematopoietic stem cell transplantation (HCT)-may result in important disease and treatment-related late effects. This study estimated physical, emotional, and educational limitations (performance limitations) and restrictions in the ability to perform personal care or routine daily activities (physical participation restrictions) and restrictions in the ability to participate in social roles (social participation restrictions) in a cohort of cancer survivors treated with HCT during childhood. Methods: Study participants included 235 persons who had a malignancy or hematologic disorder, were treated with HCT before the age of 21 years, and survived at least 2 years after transplantation. A comparison group was recruited and frequency matched for age, sex, and ethnicity. Medical data were abstracted, and patients or parents (if <18 years at survey completion) completed a mailed 24-page questionnaire. Results: Adult survivors of childhood cancer were more likely than the comparison group to report limitations in physical (prevalence odds ratio OR , 2.2; 95% confidence interval CI , 1.3-3.7) and emotional domains (OR, 2.9; 95% CI, 1.4-5.8) and to report physical participation restrictions (OR, 3.9; 95% CI, 1.9-8.2). Adult survivors were also less likely than the comparison group to be married (OR, 0.4; 95% CI, 0.2-0.6). Child survivors were more likely than similarly aged children to have participated in special education (OR, 3.0; 95% CI, 1.5-6.0), to report physical participation restrictions (OR, 10.8; 95% CI, 2.2-53.9), and to have behaviors that indicated impair-ed social competence (OR, 2.0; 95% CI, 0.9-4.2). Conclusion: This study demonstrated that persons treated with HCT as children were at increased risk for performance limitations that restricted participation in routine daily activities and interpersonal relationships. Background: Hematopoietic stem cell transplantation (HCT) -may result in important disease and treatment-related late effects. This study estimated physical, emotional, and educational limitations (performance limitations) and restrictions in the ability to perform personal care or routine daily activities ( physical participation restrictions) and restrictions in the ability to participate in social roles (social participation restrictions) in a cohort of cancer survivors treated with HCT during childhood. Methods: Study participants included 235 persons who had a malignancy or hematologic disorder, were treated with HCT before the age of 21 years, and survived at least 2 years after transplantation. A comparison group was recruited and frequency matched for age, sex, and ethnicity. Medical data were abstracted, and patients or parents (if <18 years at survey completion) completed a mailed 24-page questionnaire. Results: Adult survivors of childhood cancer were more likely than the comp arison group to report limitations in physical (prevalence odds ratio OR, 2.2; 95% confidence interval CI, 1.3-3.7) and emotional domains (OR, 2.9; 95% CI, 1.4-5.8) 3.9; 95% CI, 1.9-8.2). Adult survivors were also less likely than the comparison group to be married (OR, 0.4; 95% CI, 0.2-0.6). Child survivors were more likely than older aged children to have participated (OR, 3.0; 95% CI, 1.5-6.0), to report physical participation restrictions (OR, 10.8; 95% CI, 2.2-53.9), and to have had that impair impair- social qualities (OR, 2.0; 95% CI, 0.9-4.2). Conclusion: This study demonstrates that persons treated with increased risk of performance for that restricted participation in routine daily activities and interpersonal relationships.