Variability in approaches to define and classify disability has constituted persistent problems in documenting the epidemiology of disability and providing appropriate services. The major institutions of health care, mental health, and welfare often have separate systems of classification and terminology related to defining eligibility for programs and funding for services. In 1980, the International Classification of Impairments, Disabilities and Handicaps-ICIDH was published by the World Health Organization as a companion document of the International Classification of Disease to document the consequences of illness or injury. Current problems concerning the classification of childhood disability in health, education, and related services have resulted in growing interest in the revision of the ICIDH as a classification tool. The strengths and limitations of the ICIDH are examined in general, as well as with specific reference to its ability to document the nature and epidemiology of childhood disability. This paper (1) describes the ICIDH taxonomy and representative contributions; (2) reviews issues and concerns contributing to its revision; (3) summarizes changes in the revised ICIDH2 draft document, and (4) identifies issues of particular relevance to children and public health applications.