The article describes a psychosocial model of intervention with psychiatric patients in long-term hospitalization in a psychiatric ward in Israel and reports the findings of the evaluation conducted of its effectiveness. The model was aimed at maintaining or improving the patients' functioning in four main areas: personal hygiene, environmental maintenance, occupational competency, and social and recreational activities. For each patient, an individualized intervention program was designed and implemented by a personal case manager appointed from the ward's clinical staff. The programs involved family and ward staff as well as the patients themselves. The evaluation, based on comparison of monthly data for 4 months before and 12 months during the intervention, showed significant improvement in all but two areas of functioning: social functioning and psychiatric status. The findings, although in need of confirmation in larger, representative samples of patients in Israel and elsewhere, hold promise for effective intervention with patients whose treatment today consists largely of medication. (Contains 1 table and 1 figure.)