A unique aspect of soccer is the use of the head for directing the ball. The potential for resultant head injuries has been the focus of discussions worldwide. Prior work has attributed neuropsychologic deficits to the cumulative effects of heading, without evaluating concussion rates in soccer players. We prospectively studied the seven men's and eight women's varsity soccer teams in the Atlantic Coast Conference during two seasons to document concussion incidence. The 29 concussions diagnosed over the 2 years in 26 athletes, 17 (59%) concussions in men and 12 (41%) in women, resulted from contact with an opponent's head (8, 28%), elbow (4, 14%), knee (1, 3%), or foot (1, 3%); the ball (7, 24%); the ground (3, 10%); concrete sidelines (1, 3%); goalpost (1, 3%); or a combination of objects (3, 10%). Twenty concussions (69%) occurred in games; none resulted from intentional heading of the ball. The basic incidence was 0.96 concussions per team per season. The overall incidence was 0.6 per 1000 athlete-exposures for men, and 0.4 per 1000 athlete-exposures for women. By concussion grade, there were 21 (72%) grade 1, 8 (28%) grade 2, and no grade 3 concussions. These findings suggest that concussions are more common in soccer than anticipated and that acute head injuries may have potential for long-term neuropsychologic changes.