A neurologic and neuropsychologic test battery was administered to a sample of 35 children drawn from all those in a defined geographic area who had been hospitalized for head trauma before age 7 during the years 1970-1976. Examination was performed 3 1/2 to 10 years after injury, at age 6-15. Twelve subjects had been diagnosed at the time of injury as suffering moderate insult and had been referred to the metropolitan neurosurgical center, while twenty-three with only mild injury had been retained for observation in a local pediatric ward. The twelve with more severe insult were significantly inferior to the other subjects on the Block Design and Coding subtests of the revised Wechsler Intelligence Scale for Children. The Koppitz score of the Bender Test, the WISC-R scatter, the Benton Visual Retention Test, the GATB Motor Speed Test and the Bourdon-Wiersma Vigilance Test showed less diagnostic power and failed to distinguish between the group with more severe injury and that with less. A detailed and carefully scored neurologic examination also failed to distinguish between the two groups. The findings suggest that relatively common traumatic injury may be associated with detectable late cognitive deficit, and that some WISC-R subtests may be among the best measures for detecting such deficit.