Background: The World Health Organization has adopted two classifications relating to disability, one was published in 1980 and the more recent one in 2001. Although the international classification of functioning, disability and health (ICF) was drafted as a revision of the international classification of impairments, disabilities and handicaps (ICIDH), the ICF is based on major changes when compared with the ICIDH. One of them has to do with the environment. Method: Quotations from the classification manuals and related articles are presented in order to make clear the scope of the environment in the ICF. Results: The ICF has a universal application. The gap between capacity and performance reflects the barriers created by the environment. Conclusions: In the ICF, universalism and barriers have specific meanings, reflecting specific policy choices.