The present study investigated the relationship between elevated heart rate (HR) and posttraumatic stress disorder (PTSD) 6 months following accidental pediatric injury. The HR was taken in 101 children, aged 7 to 16 years, upon arrival at the hospital and again 24 hours following admission. Posttraumatic stress disorder was assessed 6 months later using the Anxiety Disorders Interview Schedule for DSM-IV (W. K. Silverman & A. M. Albano, 1996). Children who had an elevated HR (defined as greater than/equal to one standard deviation above the age and sex mean) at admission or 24 hours later were more likely to experience traumatic stress symptoms at 6 months. These findings suggest elevated HR could be used to aid in the early identification of children at risk of developing PTSD following a traumatic accident.