This article analyses changing conceptions of disability through a discussion of the two disability classifications published by the World Health Organization (WHO) and the Handicap Production Process (HPP) (1988-1998) that paved the way for the shift from the International Classification of Impairments, Disabilities and Handicaps (ICIDH) (1980) to the International Classification of Functioning, Disability and Health (ICF) (2001). The two WHO classification systems are based on distinct theoretical approaches that evolved from the biological and individualized view of disabilities produced by the International Classification of Diseases (ICD) to a social approach incorporating the idea of human rights. The theoretical foundations of these classifications imply consequences for society that should be considered, in our view, because they contribute, in particular, to the changing standards of reference used to define disabilities.