The authors examine the problem of dementia from a theoreticalpractical point of view with special reference to psychiatric rehabilitation and to the contributions by the health and social systems. A case of presenile dementia is presented and the basic principles of intervention are described, which consist in 1) early diagnosis which allows the immediate realization of a specific rehabilitation program aiming at the patient's reintegration into his or her environment and at the maximal utilization of his or her residual capacity; and 2) the involvement of the families in the program and the psychological and social help necessary to sustain them in their effort. The authors discuss then to what extent this type of intervention is feasible in the context of a community psychiatric service as prescribed by the Italian psychiatric reform known as Law 180.