Steadiness and stability limits are two main indices for measuring balance ability. Functional reach test, a test of stability limits in the anterior direction, has been used to differentiate between elderly fallers and nonfallers. This study examined the stability limits in the anterior, posterior, left, and right directions in healthy subjects of different ages. Three groups of subjects were recruited, an old adult group (73.1±7.6 years old), a young adult group (21.1±1.9 years old), and a children group (9.2±1.8 years old). Subjects were tested on a Balance Performance Monitor (SMS Healthcare, UK) for their ability to maintain maximal leaning postures in the 4 directions, each direction was tested for 30 seconds. The sequence of direction tested was balanced among subjects. The results revealed that the maximal leaning amplitude in the young adults was significantly greater than the older subjects, the children had similar amplitude to the young adults. Except in the anterior direction, children were fastest to reach the maximal leaning amplitude among age groups. The fatigue index (the difference between the maximal leaning amplitude and the leaning amplitude at 30 second) was not different among groups. The balance coefficient (left/right footplate loading) revealed that children were less symmetrical than old adults while leaning toward the posterior direction. However, when leaning laterally, the children were better able to shift weight onto either legs than the older adults. In terms of the sway coefficient (a measure of steadiness at the maximal leaning posture), the children had more sway in the anteroposterior direction whereas the young adults had more sway in the lateral directions. The significance level was set at p＜.05. Despite of small sample sizes, this study found some interesting differences in the stability limits among age groups. Future study is suggested to investigate the effect of vision on stability limits.