INTRODUCTION: Attention Deficit Hyperactivity Disorder (ADHD) and previous history of concussion (PHC) are being reported more frequently in college athletes; the presence of these co-morbidities and their effects on concussion assessment has been somewhat limited. PURPOSE: Determine if a relationship exists between ADHD and PHC and the effect of these co-morbidities on neuropsychological test scores. METHODS: This study was a retrospective cross-sectional between groups design. D-1 college athletes (N=1840, males N=1737, females N=103) with a mean age of 19.8+1.6 years completed a computerized neuropsychological test (ImPACT) to establish baseline assessment of concussion history during pre-participation physicals. Participants were divided into groups based upon self-reported diagnosis of ADHD and PHC. Self-report symptoms and ImPACT composite scores served as dependent variables. Comparisons of groups were calculated utilizing regression models and One-Way ANOVAs. All statistical analyses were conducted utilizing STATA 9.0. RESULTS: 102 (5.5%) participants self-reported a diagnosis of ADHD. 486 (26.5%) of the participants self-reported a history of concussion. There was a difference between ADHD and controls for self-reported symptoms (F (1, 1838) = 26.226, p > 0.001, Composite Verbal Memory (F (1, 1838) = 10.02, p = 0.002), Composite Motor (F (1, 1838) = 5.96, p = 0.015), Composite reaction time (F (1, 1838) = 3.94, p = 0.047). No statistical differences were found between the PHC group and normal counterparts. There was a difference for the interaction between ADHD and PHC on Composite Verbal Memory (F (5, 1834) = 2.44, p= 0.0325). CONCLUSIONS: The increase of media and clinician awareness of PHC and ADHD diagnoses has increased reporting during baseline assessment. Significant differences existed between groups with participants with ADHD and participants with ADHD and PHC performing below their “normal” counterparts. Previous literature supports the potential additive effect of learning disabilities and PHC; however this subgroup of ADHD did not replicate previous findings. The increase of ADHD and PHC diagnoses demands that health care practitioners understand the implications and effects of these disabilities on neuropsychological tests utilized in concussion assessment.