The ability to balance is closely related to funtional status and safety. It is of particular concern in the elderly as balance may be impaired due to disease or aging. The primary objective of this paper is to review existing laboratory and clinical measures of balance. To facilitate this review, the dimensions of balance and the properties of good measurement are described. Situations requiring balance can be divided into three general classifications: maintenance of a position, postural adjustment to voluntary movements, and reactions to external stresses. This complex motor skill may be viewed from a biomechanical, a neurophysiological, or a functional perspective. In the laboratory, investigators have measured sway patterns and examined strategies of regaining balance after a perturbation. Recent clinical studies have shown a trend to performance based assessment. To date there is no one universally acceptable laboratory or clinical method to measure balance. Because of its importance in functional activities, the need for a good measure of balance is evident.