Adults with Down syndrome (DS) are often physically inactive, which may accelerate the onset of disease and aging symptoms. Eight older persons with DS (aged 54-61), and 10 younger persons with DS (aged 26-35) living in a residential care center were examined. Eighteen age- and gender-matched individuals without DS served as control groups. Sensory-motor tasks and Posture Scale Analyzer (PSA) were used to examine coordination and standing stability. The isokinetic muscle strength test was used for muscle strength investigation. The functional performance, coordination, and leg muscle strength of the older adults with DS were more impaired than both the younger DS and the control groups. The older DS group showed lower sway rate and more symmetrical weight-bearing distribution during quiet standing than both the younger DS and the control groups. Our observations may have significant implications for understanding movement dysfunction in older adults with DS. (Contains 5 tables.)