Physical activity preserves neurocognitive functioning in older adults by increasing brain blood flow and preserving neurotransmitter activity. Because the frontal lobes show the greatest decline, the most apparent difference was expected between physically inactive versus active individuals when performing tasks that challenge frontal lobes. Adults (66-92 years) with varied physical activity levels were administered binaural auditory oddball and go-nogo tasks. The nogo trials challenged executive processes through response inhibition. Physical activity was indexed with the Yale Physical Activity Survey. EEG was recorded from frontal, central, and parietal sites. Multiple regression analysis revealed that the overall relationship of P300 amplitude to age and physical activity was significant during nogo trials at site F3, F (2, 75) = 3.61, p = .032 and at site FZ, F (2, 75) = 6.26, p = .003. In summary, physical activity is associated with a specific effect on the aging brain revealed during executive challenge.