Acute stress disorder (ASD) and posttraumatic stress disorder (PTSD) were examined in 334 parents of children with traffic-related injuries. In the first month after their child's injury, 12% of parents had ASD and another 25% had partial ASD. Among 251 parents assessed again approximately 6 months postinjury, 8% had PTSD and another 7% had partial PTSD. The ASD and PTSD severity were associated (r = .54), but ASD status was not a sensitive predictor of later PTSD. Independent predictors of ASD severity included prior trauma exposure, peritrauma exposure and perceptions of the child's pain and life threat, and child ASD severity. Independent predictors of PTSD severity included prior trauma exposure, parent ASD severity, and parent-rated child physical health at follow-up.