In my presentation I will review research conducted in our laboratory, and the field in general, which has examined the extent to which fitness training and physical activity enhances cognition and brain structure and function of older adults. The presentation will cover both cross-sectional and intervention studies of fitness differences and fitness and physical activity training. Studies which assess cognition via both behavioral measures and non-invasive neuroimaging measures, such as magnetic resonance imaging, functional magnetic resonance imaging, event-related brain potentials, and the event-related optical signal, will be reviewed and discussed. Finally, I will explore the gaps in the human and animal literature on cognitive and brain health and the manner in which they can be addressed in future research.