Objective: To investigate the optimal combination of dietary polyphenols associated with the long-term risk of dementia in a large prospective French cohort of older persons, the Three-City (3C) Study. Methods: We included 1,329 non-demented older adults from the 3C Study with assessment of intake of 26 polyphenol subclasses and followed for 12 years for dementia. Using Partial Least Square for Cox models, we identified a pattern of polyphenol intake associated with dementia risk. Results: The pattern combined several flavonoids (dihydroflavonols, anthocyanins, isoflavonoids, flavanones), stilbenes (including resveratrol), lignans and other subclasses (hydroxybenzaldehydes, naphtoquinones, furanocoumarins). Compared with participants in the lower quintile of pattern score, those in the higher quintile had a 50% lower risk of dementia (95% CI 20%; 68%, p-trend <0.01) in multivariate models. Conclusions: In this French cohort, a polyphenol pattern provided by a diet containing specific plant products (nuts, citrus, berries, leafy vegetables, soy, cereals, olive oil) accompanied with red wine and tea was associated with lower dementia risk.