['The aim of this study was to examine the utility of a hierarchical algorithm incorporating codes from the International Classification of Functioning, Disability and Health--ICF (WHO, 2001) and the International Statistical Classification of Diseases-ICD (WHO, 1994) to classify reasons for eligibility of young children in early intervention.', 'The database for this study was a nationally representative enrollment sample of more than 5,500 children in a longitudinal study of early intervention. Reasons for eligibility were reviewed and matched to the closest ICF or ICD codes under one of four major categories (Body Functions/Structures, Activities/Participation, Health Conditions, and Environmental Factors).', 'The average number of reasons for eligibility provided per child was 1.5, resulting in a population summary exceeding 100%. A total of 305 ICF and ICD codes were used with most (77%) of the children having codes in the category of Body Function/Structures. Forty-one percent of the sample had codes of Health Conditions, whereas the proportions with codes in the Activities/Partipication and Environmental Categories were 10 and 5%, respectively.'] Do iCF and ICD codes provide a standard language of disability in young children?