Social exclusion manifests itself in the persistent lack of an individual's access to functionings as compared to other members of society and we model it as being in a state of deprivation over time. We view deprivation as having two basic determinants: the lack of identification with other members of society and the aggregate alienation experienced by an agent with respect to those with fewer functioning failures. Using an axiomatic approach, we characterize new individual and aggregate measures of deprivation and of social exclusion. The aggregate measures are then applied to EU data for the period from 1994 to 2001.