Rehabilitation aims at avoiding unfavourable consequences of a disorder and its care and at training and improving impaired and compensatory skills. The needs of the main diagnostic groups with resulting cognitive or social impairments, namely mental retardation, infantile autism, chronic depression, severe psychoneurosis, substance abuse, schizophrenia, and dementia in old age, have specific aspects. An increased need for rehabilitation was prompted by the worldwide movement of deinstitutionalisation, which hit above all the socially most vulnerable schizophrenics. The instruments and methods of rehabilitation for the socially disabled mentally ill go far beyond the sphere of psychiatry. Individualised rehabilitation must be in mutual interaction with the social and occupational environment. The socially disabled individual is, for example, dependent upon awareness and acceptance in the community, upon financial and social support or upon the availability of a job. In the case of persisting deficits, supportive measures at different levels are needed to compensate or to minimize severe consequences of impairments. Their approach is by the social environment with the objective to grant the optimum quality of life combined with a minimum loss of independence. The great variety of measures often required at the same time must be based on a network of services and their purposeful coordination. Psychiatric rehabilitation requires a functioning social system and, in times of scarce resources, political priorities.