OBJECTIVE: To evaluate the properties of the cognitive battery used in the MIND Diet Intervention to Prevent Alzheimer's Disease. The MIND Diet Intervention is a randomized control trial to determine the relative effectiveness of the MIND diet in slowing cognitive decline and reducing brain atrophy in older adults at risk for Alzheimer's dementia. METHODS: The MIND cognitive function battery was administered at baseline to 604 participants of an average age of 70 years, who agreed to participate in the diet intervention study, and was designed to measure change over time. The battery included 12 cognitive tests, measuring the 4 cognitive domains of executive function, perceptual speed, episodic memory, and semantic memory. We conducted a principal component analysis to examine the consistency between our theoretical domains and the statistical performance of participants in each domain. To further establish the validity of each domain, we regressed the domain scores against a late-life cognitive activity score, controlling for age, race, sex, and years of education. RESULTS: Four factors emerged in the principal component analyses that were similar to the theoretical domains. In regression equations, we found the expected associations with age, education, and late-life cognitive activity with each of the four cognitive domains. CONCLUSIONS: These results indicate that the MIND cognitive battery is a comprehensive and valid battery of four separate domains of cognitive function that can be used in diet intervention trials for older adults.