A new 13-item. version of the Impact of Event Scale (Horowitz, Wilner, & Alvarez, 1979) was adminstered to 2976 9-14 year old children from Bosnia as part of a large epidemiological screening survey. The IES-13 consists of four intrusion items, four avoidance items, and five new arousal items. Factor analyses showed the scale to have an identical underlying factor structure as when it was used with British children who experienced a single-incident trauma. In addition, there was also a third factor of hyperarousal, closely related to intrusion. These results are discussed in the context of the cross-cultural validity of post traumatic stress reactions in children. (C) 2002 Elsevier Science Ltd. All rights reserved.