The present study reviews currently available methods of estimating premorbid intellectual abilities in children, and examines the potential of the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV; Wechsler, 2003) as an estimate of premorbid IQ in children with Traumatic Brain Injury (TBI). Archival data were obtained from a sample of 2,200 children aged 6:0--16:11 who participated in the standardization phase of the WISC-IV, and 43 children aged 6:0--16:11 with a history of moderate or severe TBI who participated in a WISC-IV special group study. First, demographic variables including sex, ethnicity, parent education level, and geographic region were entered into a regression analysis to determine a demographic-based premorbid prediction equation for the WISC-IV Full Scale Intelligence Quotient (FSIQ). Second, a logistic regression analysis was used to investigate which WISC-IV subtest scaled scores improve the differential diagnosis of TBI versus a matched control group. Third, an ANOVA was used to examine which subtests yielded the lowest mean scores for the TBI group. The results support previous research that shows parental education is the strongest predictor of premorbid IQ and that ethnicity is an important contributor in the demographic equation. In addition, the findings show that a three-variable model consisting of the Coding Copy, Block Design, and Comprehension subtests significantly improved the prediction of correctly classifying TBI versus matched control. Furthermore, as expected, the results show that the TBI group produced the lowest scores on the Processing Speed Index and the Working Memory Index.