Background: Cognitive reserve (CR) is the ability to counteract brain damage through differential recruitment of brain networks. Besides, it has also been observed that lifetime intellectual enriching skills reduce the effect of disease burden on cognitive status. The Cognitive Reserve Index questionnaire (CRIq), which is a method for the quantitative measurement and comprehensive evaluation of the CR, that individuals have accumulated throughout their lifetimes. The present study aimed to adapt CRIq to the Turkish population. Methods: CRIq is a 20-item questionnaire consisting of 3 sub-scales (CRI-Education, CRI- Working Activity, CRILeisure Time). 271 females and 228 males, a total of 499 healthy volunteers participated in the study (mean age: 39.54?14.05, mean education years 13.14?4.84). Participants were evaluated with the ?Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS)? and CRIq was applied. BICAMS was used to determine the validity of the CRIq. To determine the reliability, the questionnaire was applied again two weeks after the first application. Internal consistency and test-retest reliability were measured for reliability analysis. Independent sample t-test was conducted to observe the difference between genders. Results: The Cronbach alpha coefficient of the questionnaire was 0.78, and the reliability of the questionnaire was acceptable. The findings showed that inter-rater reliability was quite high (ICC:0.95, 95% CI=1.000, n=36). The correlation between the first and second application of the questionnaire was found to be acceptable for both the sub-scales and the whole questionnaire. The highest CRIq scores were shown for young adults in CRI-Education and CRI-LeisureTime, for the middle-aged in CRIq-WorkingActivity, no significant differences in total CRIq scores. The males scored significantly higher in CRIq total scores than females, but there was not a significant difference in CRI-LeisureTime between genders. Conclusion: The Turkish version of CRIq was found to be a valid and reliable method for evaluating cognitive reserve in healthy individuals.