French researchers compared women aged 65 and older who drank more than three cups of coffee per day with those who drank one cup or less per day.
Those who drank more caffeine showed less decline in memory tests over a four year period.
The study, published in the journal Neurology, raises the possibility that caffeine may even protect against the development of dementia. The results held up even after factors such as education, high blood pressure and disease were taken into account.
Caffeine is a known psychostimulant, but this study appears to suggest its effects may be more profound.
However, lead researcher Dr Karen Ritchie of the French National Institute for Health and Medical Research warned against jumping to premature conclusions.
She said: "While we have some ideas as to how this works biologically, we need to have a better understanding of how caffeine affects the brain before we can start promoting caffeine intake as a way to reduce cognitive decline. But the results are interesting - caffeine use is already widespread and it has fewer side effects than other treatments for cognitive decline, and it requires a relatively small amount for a beneficial effect."
The study, which involved 7,000 women, did not find that caffeine consumers had lower rates of dementia.
Source - BBC