The extent to which changes in blood-brain-barrier permeability are associated with healthy aging is poorly understood. Pharmacokinetic modeling of dynamic-contrast-enhanced MRI yields quantitative estimates of BBB water permeability. DCE-MRI data were collected from 40 healthy controls (aged 34-80 yrs) at 7T. Declines in pharmacokinetic parameters were significant across the entire age range included in this study. Because changes in BBB permeability to water and other small molecules are likely to precede the leakage of CR and larger macromolecules, these estimates represent particularly important probes of the subtle BBB abnormalities that are likely to accompany healthy brain aging.