The recent formulation of guidelines for the management of concussion in sports adopted by the American Academy of Neurology specifically calls for the development of a standardized, systematic sideline evaluation for the immediate assessment of concussion in athletes, The present study involved the preliminary investigation of the feasibility and clinical validity of a standardized version of a brief sideline examination complied in accordance with these guidelines, This examination, intended for use by athletic trainers, was administered by three trainers to 141 nonconcussed high school football players at three separate schools, All players suspected of suffering a concussion (N = 6) during the fall 1995 season were also tested immediately following their injury. The examination was easily administered and scored, The concussed players as a group scored significantly below the nonconcussed controls and below their own baseline (pre-injury) performance, despite their all having been considered by the trainers to have suffered mild, grade 1 concussions. Although preliminary, these data suggest that a standardized sideline examination of this type can be useful in detecting concussion and determining fitness to return to play.