BACKGROUND Functional decline in physically frail, elderly persons is associated with substantial morbidity. It is uncertain whether such functional decline can be prevented. METHODS We randomly assigned 188 persons 75 years of age or older who were physically frail and living at home to undergo a six-month, home-based intervention program that included physical therapy and that focused primarily on improving underlying impairments in physical abilities, including balance, muscle strength, ability to transfer from one position to another, and mobility, or to undergo an educational program (as a control). The primary outcome was the change between base line and 3, 7, and 12 months in the score on a disability scale based on eight activities of daily living: walking, bathing, upper- and lower-body dressing, transferring from a chair, using the toilet, eating, and grooming. Scores on the scale ranged from 0 to 16, with higher scores indicating more severe disability. RESULTS Participants in the intervention group had less functional decline over time, according to their disability scores, than participants in the control group. The disability scores in the intervention and control groups were 2.3 and 2.8, respectively, at base line; 2.0 and 3.6 at 7 months (P=0.008 for the comparison between the groups in the change from base line); and 2.7 and 4.2 at 12 months (P=0.02). The benefit of the intervention was observed among participants with moderate frailty but not those with severe frailty. The frequency of admission to a nursing home did not differ significantly between the intervention group and the control group (14 percent and 19 percent, respectively; P=0.37). CONCLUSIONS A home-based program targeting underlying impairments in physical abilities can reduce the progression of functional decline among physically frail, elderly persons who live at home.