The ability of the Pediatric Trauma Score (PTS) to accurately predict the degree of injury severity of the injured child was assessed by comparing two separate groups of pediatric trauma victims. The first group consisted of 110 patients evaluated at a regional pediatric trauma center whose data was collected and assessed by a single investigator. The second group consisted of a similar matched cohort of 120 patients from the National Pediatric Trauma Registry whose data was collated from multiple participating institutions. In both cases, a linear relationship between PTS and Injury Severity Score (ISS) was documented that was statistically significant to P less than .001. The linear regression coefficients of each group were similar as was the distribution of PTS and ISS. This study documents the validity of the PTS as an initial assessment tool and confirms its reliability as a predictor of injury severity.