CKDis linkedwith various braindisorders.Whereas brain integrity is dependent on cerebral perfusion, the association between kidney function and cerebral blood flow has yet to be determined. This study was performed in the framework of the population-based Rotterdam Study and included 2645 participants with mean age of 56.6 years (45% men). We used EGFR and albumin-to-creatinine ratio to assess kidney function and performed phase-contrast magnetic resonance imaging of basilar and carotid arteries to measure cerebral blood flow. Participants had an average (SD) EGFR of 86.3 (13.4) ml/min per 1.73m2andamedian(interquartile range) albumin-to-creatinine ratio of 3.4 (2.2-6.1)mg/g. In age-and sex-adjustedmodels, a higher albumin-to-creatinine ratio was associated with lower cerebral blood flow level (difference in cerebral blood flow[milliliters per minute per 100 ml] per doubling of the albumin-to-creatinine ratio, 20.31; 95% confidence interval, 20.58 to20.03). The association was not present after adjustment for cardiovascular risk factors (P=0.10). Each 1 SD lower EGFR was associatedwith 0.42ml/min per 100 ml lower cerebral blood flow(95% confidence interval, 0.01 to 0.83) adjusted for cardiovascular risk factors. Thus, in this population-based study, we observed that lower EGFR is independently associated with lower cerebral blood flow.