Our aim was to evaluate the association between adherence to the Mediterranean Diet (MedDiet) and cognitive function in 823 participants (62 ± 6 years at baseline) from a Spanish prospective cohort (SUN project).A validated 136-item food frequency questionnaire was used to assess the adherence to the MedDiet at baseline. The 10-point (0 to 9) MedDiet Score was used to categorize adherence to MedDiet. Cognitive function was assessed twice at follow-up with a mean follow-up time between exposure and outcome assessment of 6 and 8y using the Telephone Interview of Cognitive Status-modified (TICS-m, range 0 to 54 points). ANCOVA models were used to assess the association between adherence to the MedDiet and cognitive decline.In the multivariable-adjusted analysis of 2-year changes, a higher cognitive decline was observed among participants with low or moderate baseline adherence to the MedDiet than among those with better adherence (adjusted difference = -0.56 points in TICS-m, 95% CI = -0.99 to -0.13).A higher adherence to the MedDiet might be associated with better cognitive function. However, observed differences were of small magnitude and further studies are needed to confirm this finding.