OBJECTIVE: Poor cardiovascular fitness has been implicated as a possible mechanism for obesity-related cognitive decline, though no study has examined whether BMI is associated with poorer cognitive function in persons with excellent fitness levels. The current study examined the relationship between BMI and cognitive function by the Immediate Post Concussion and Cognitive Test (ImPACT) in Division I collegiate athletes. METHODS: Participants had an average age of 20.14 +/- 1.78 years, were 31.3% female, and 53.9% football players. BMI ranged from 19.04 to 41.14 and averaged 26.72 +/- 4.62. RESULTS: Regression analyses revealed that BMI incrementally predicted performance on visual memory (R(2) change = 0.015, p = 0.026) beyond control variables. Follow-up partial correlation analyses revealed small but significant negative correlations between BMI and verbal memory (r = -0.17), visual memory (r = -0.16), and visual motor speed (r = -0.12). CONCLUSIONS: These results suggest that higher BMI is associated with reduced cognitive function, even in a sample expected to have excellent levels of cardiovascular fitness. Further work is needed to better understand mechanisms for these associations.