The performance of 38 5–8-year-old children with traumatic brain injury (TBI) on the Children's Category Test-Level 1 (CCT-1; Boll, 1993) was investigated in order to examine the criterion validity of the component subtests. Only subtests III and V varied in a consistent and meaningful manner with levels of injury severity and post-injury psychometric intelligence. In contrast, 21% of the sample performed at chance level on subtest IV, a task that did not demonstrate any criterion validity. It is concluded that when a substantial proportion of the total errors (e.g., ≥50%) on the CCT-1 pertain to items from subtest IV, interpretation of the composite summary T score may not be valid.