This chapter draws attention to several philosophical issues raised by the phenomenon of disablement and then focuses on two main ones pertinent to philosophy of medicine: the definition of disability and the relationship between disability and identity. Two kinds of approach are identified in relation to the question of the definition of disability, one of which focuses on the individual concerned and is sometimes described as a "medical model" of disability and another approach which places more emphasis on the environment beyond the individual. The World Health Organization's (WHO) taxonomy is presented below to represent the first kind of approach, and the theory devised by Professor Lennart Nordenfelt is presented as representing the second. The chapter then turns to discuss disability and identity. It is shown that on standard ways of conceiving of the identity relation, disability seems closer to a contingent (and so non-identity-constituting) characteristic of persons as opposed to an essential, identity-constituting one. However, another strategy is also described in which certain kinds of contingent properties can be identity-constituting. So if the latter strategy proves successful, then it may be true that disability can indeed be identity-constituting.