Purpose The evidence suggests that adherence to the Mediterranean diet (MD) may be beneficial in preventing cognitive decline. We aimed to explore this association in a Central European population. Methods A total of 6,028 men and women from the Czech arm of the HAPIEE study were included in the analysis. Dietary data were collected using a food frequency questionnaire, and MD score (MDS) was calculated based on nine food groups. The MDS (range 0–17 points) was classified into three groups: low (0–7), medium (8–10), high (11–17). Cognitive function was measured using four tests assessing verbal memory and learning, verbal fluency, and attention, mental speed and concentration, and composite score, each of them converted to z-score. The associations between MDS and cognitive function were analyzed using multivariate linear regression in men and women. Results There were no significant associations in men. By contrast, women with a dietary score of 8–10 points (B=0.05, 95% CI: -0.002; 0.097), and those with a score of 11–17 points (B=0.08, 95% CI: 0.016; 0.140) had a higher composite cognitive score than women in lowest adherence group. Regarding specific domains, women in the highest adherence group had significantly better immediate verbal memory (B=0.12, 95% CI: 0.031; 0.205) and delayed recall (B=0.12, 95% CI: 0.027; 0.212), respectively, than those in the lowest adherence group. Conclusion Higher adherence to the MDS was associated with better cognitive functioning in verbal memory and composite cognitive score in Czech women. The results suggest that the Mediterranean diet may help to improve cognitive functioning.