Technical Abstract: A previous study in our laboratory determined that a blueberry-enriched antioxidant diet prevented age-related deterioration of object recognition memory. NFK -B is a protein transcription factor that is elevated in aging and by oxidative stress. The present study determined whether the antioxidant diet would attenuate the age-induced increase in NFK -B expression. The subjects were the rats from the memory study: twelve eight mo. old and eleven 19 mo. old rats that had been maintained for four mos. on a control diet and twelve 19 mo. old rats on four mos. of a blueberry-enriched diet (to 23 mo of age). The rats were anesthetized and perfused with 4% formalin and their brains were removed and dissected into 5 regions: frontal lobe, hippocampus, basal forebrain, striatum and cerebellum. Regional expression of NFkappa-B was determined by western blotting assays. Normalized densities were subjected to one-way ANOVA, followed by post-hoc pairwaise comparisons (Fisher's LSD test). In every region, ANOVA revealed significant differences among the groups. In every region, aged rats maintained on control diet had higher average NFkappa-B levels than young animals on the control diet. This difference was significant in four of the five regions. In every region, aged rats on the blueberry-enriched diet had lower levels of NFkappa-B than aged rats on the control diet. This difference was significant in four of the five regions. The difference between the young rats and the aged rats on the blueberry diet was significant in only one region (hippocampus). Normalized densities (averaged across regions and in several individual regions) correlated negatively and significantly with the object memory scores.