Objective: An estimated 38 million children in the United States engage in organized sports, and emergency room visits are increasing for children suffering sports-related concussions. Despite the need to examine the neurocognitive effects of cognition in pediatric populations, research on long-term effects of concussion in children is limited. Twin studies are a valuable resource when making comparisons; therefore, the present case study compared neurocognitive profiles of twins who differed in concussion history. Method: Two 11-year-old monozygotic male twins were evaluated pre-football season as part of a study measuring baseline neurocognitive functioning. One boy sustained a concussion eight months prior to testing. Assessment included: Delis-Kaplan Executive Function System (D-KEFS), NEPSY-II, Stroop Color-Word, Wechsler Abbreviated Scale of Intelligence – Second Edition (WASI-II), Wechsler Intelligence Scale for Children-IV (WISC-IV), and Wide Range Assessment of Memory and Learning – 2nd edition (WRAML-2). Results: The child without history of concussion scored higher on the WISC-IV Verbal Comprehension Index (.8 standard deviations - SDs), Full Scale IQ (.6 SDs), Stroop (.2 SDs), and WRAML-2 and NEPSY-II Delayed Memory (1 SD). The boy with a history of concussion scored higher on D-KEFS Trail Making Test (.9 SDs) and WISC-IV Working Memory Index (.8 SDs). Conclusion: Results suggest that one twin's concussion history may have impacted his neurocognitive functioning, particularly in the areas of verbal comprehension and delayed memory. These findings are surprising given that most research does not show lasting effects of concussion in children. This case study supports the need for additional research evaluating the neurocognitive effects of concussion in children.