With the increasing elderly population in Korea, dementia has become a mojor health problem in Korea. Several studies have been conducted on the association between dementia and dietary intake, especially vitamin E and vitamin C. The purpose of this study was to investigate the effect of vitamin E and vitamin C supplementation on the decrease in cognitive function induced by scopolamine(300mg/kg) in rats. Rats were divided into three groups : control, vitamin C, and vitamin E supplementation(2.4g Vit C or Vit E /100g diet) and fed the diets for 6 weeks. There were significant decreases in active avoidance response and brain acetylcholinesterase activity in the control group, but no significant differences were observed in the vitamin E and C groups after scopolamine treatment. Brain dopamine concentration of vitamin E and C groups was significantly higher than those of control group after scopolamine injection. The concentrations of brain norepinephrine also showed similar tendence, even though it was not statistically significant. These results indicate that vitamin E and vitamin C may protect against the cognitive function decrease induced by scopolamine. However, it is still unclear how vitamin E and C influence brain neurotransmitters and improve cognitive function. Further study is need to elucidate the role of vitamin E and C supplementation in the prevention of dementia.