The purpose of this study was to determine the effects of closed-head injury upon postural sway. Forty-eight subjects (26 males and 22 females) between the ages of 18 and 45 were equally divided into four groups corresponding to their level of head injury. Group 1 had not incurred a head injury, group 2 members incurred head injuries but did not lose consciousness, group 3 lost consciousness for less than 6 h, and group 4 lost consciousness for greater than 6 h. All subjects were at least 1 yr postinjury. Each subject performed three trials of six variations of the Romberg test. The center of pressure transmitted through the bottom of the feet was monitored during each 30-s trial. Total, anterior-posterior (AP), and medial-lateral (ML) sway was calculated from center of pressure data. The severely head-injured group generally evidenced greater AP sway than the other three experimental groups for all but one test condition. It was concluded that closed-head injury, particularly when associated with relatively long periods of unconsciousness, results in postural instability.