Objectives, social role and organization of Italian nursing homes (RSA) are characterized by a pronounced regional differentiation that causes situations which are difficult to compare about expected outcomes. The definition of a functional outcome is particularly difficult in institutionalized patients and this is due to the failure of a conclusive moment of the rehabilitative treatment. Furthermore we often take care of patients who have already been admitted to intensive and/or extensive rehabilitation units time after time, without further functional profit margin. The inconstant presence of professional figures of rehabilitation in nursing homes' staff makes difficult the drafting of an adequate rehabilitative project, especially for the multiple needs of frail old people. Starting with these assumptions, authors hypothesize and adopt a model of sanitary organization to consent a correct allocation of available resources, according to the patient's needs. They stratified all nursing home patients, using the Multidimensional Prognostic Index (MPI) and "Scheda di osservazione intermedia assistenza" (SOSIA), and measured the residual function. They concluded that a multidimensional evaluation of patients allows to identify wellness (of the sick person and of caregivers) as the main objective; nursing home organization could be think as a "complex supportive prosthesis for old people", made by the interaction among structure, operators and activities.