The goals were to examine: (1) the frequency and intensity of all PTSD symptoms and evaluate the relation to clinical impairment; (2) the requirement of meeting all symptom cluster criteria; and (3) the aggregation of PTSD symptom clusters across developmental stages. The Clinician-Administered PTSD Scale for Children and Adolescents was used to assess 59 children between the ages of 7 and 14 years with a history of trauma and PTSD symptoms. The data supported the utility of distinguishing between the frequency and intensity of symptoms. The intensity of the avoidance of feelings, thoughts, and conversations and distress at exposure to cues predicted functional impairment, whereas the frequency of these symptoms was not predictive of impairment. Findings also supported the hypothesis that children with subthreshold criteria did not differ significantly from children meeting all three cluster criteria with regard to impairment and distress. Results suggest that rather than seeking a threshold number of symptoms, a more precise diagnosis of pediatric PTSD could be developed by evaluating the intensity of symptoms and their relation to functional impairment. Finally, findings suggest that developmental modifications to symptom clusters C (Avoidance and Numbing) and D (Hyperarousal) as done with B (Reexperience) may be useful. There was evidence of increased aggregation of the clusters with pubertal development. Children with subthreshold PTSD should be evaluated for functional impairment and distress and be given appropriate recommendations for treatment even when they do not fulfill DSM-IV criteria. 3 tables, 34 references