Historically WHO has concentrated on infection control and mortality reduction. However, diagnosis alone does not explain what patients can do, what their prognosis will be. To answer these questions, significant challenges are presented in model the International Classification of Impairment, Disability and Handicap (ICIDH) announced in 1980. Following several revisions of ICIDH, WHO (2001) finally approved the International Classification of Functioning, Disability and Health (ICF), which is universal and clear terminology with qualifiable assessment measures. The ICF is a new form which (1) is not based on disability, rather on human function, (2) is interactive rather than linearly progressive, and (3) is not medical or social model, rather integration model. Also, the new language ICF is an landmark event for rehabilitation. Key to successful rehabilitation management is the understanding and proper assessment of the relationship between disease (ICD-10) and impaired body functions and structures and psychosocial and environmental factors(ICF). (J Korean Acad Rehab Med 2004; 28: 401-411)
