A unique feature of soccer is the purposeful use of the head for controlling, passing, and shooting a soccer ball. Some concern has been expressed in the literature on the cumulative effects of heading on soccer players. Certain neurophysiologic and neuropsychologic changes have been reported in current or retired players, with heading being blamed. A major factor that could influence some of the findings is a player's history of concussive episodes, which are known to influence brain function. These episodes can occur during aspects of the game other than heading. We interviewed all male and female soccer players (N = 137, average age = 20.5 years) who competed at the U.S. Olympic Sports Festival in 1993. The mechanisms of injuries, frequency, and sequelae were determined. There were 74 concussions in 39 male players (grade I = 50) and 28 concussions in 23 female players (grade I = 19). For the men, 48 of the 74 episodes were from collisions with another player. For the women, 20 of 28 were from such collisions. Headaches, being "dazed," and dizziness were the most common symptoms reported. Based on concussion history, the odds are 50% that a man, and 22% that a woman, will sustain a concussion within a 10-year period. The data indicate that concussions from player-to-player contact are a frequent hazard in soccer. Head injuries incurred this way may be more of an influence for published findings of physiologic and psychologic deficiencies than routine heading of the soccer ball.