This study investigates the longitudinal changes in brain tissue volume in older adults using magnetic resonance imaging (MRI) scans from the Baltimore Longitudinal Study of Aging. The researchers analyzed MRI data from 92 non-demented participants aged 59 to 85 years at baseline, with follow-up assessments at 2 and 4 years. They found significant age-related decreases in both gray and white matter volumes, with annual rates of 5.4 cm³, 2.4 cm³, and 3.1 cm³ for total brain, gray matter, and white matter, respectively. Ventricular volume increased by 1.4 cm³ per year. The decline was more pronounced in frontal and parietal regions compared to temporal and occipital regions. Gray matter loss was most significant in orbital and inferior frontal, cingulate, insular, and inferior parietal regions, while white matter changes were widespread. These findings provide essential information on the rate and regional pattern of age-associated brain tissue loss, even in healthy older adults, and suggest that individuals who remain medically and cognitively healthy may have slower rates of brain atrophy.This study investigates the longitudinal changes in brain tissue volume in older adults using magnetic resonance imaging (MRI) scans from the Baltimore Longitudinal Study of Aging. The researchers analyzed MRI data from 92 non-demented participants aged 59 to 85 years at baseline, with follow-up assessments at 2 and 4 years. They found significant age-related decreases in both gray and white matter volumes, with annual rates of 5.4 cm³, 2.4 cm³, and 3.1 cm³ for total brain, gray matter, and white matter, respectively. Ventricular volume increased by 1.4 cm³ per year. The decline was more pronounced in frontal and parietal regions compared to temporal and occipital regions. Gray matter loss was most significant in orbital and inferior frontal, cingulate, insular, and inferior parietal regions, while white matter changes were widespread. These findings provide essential information on the rate and regional pattern of age-associated brain tissue loss, even in healthy older adults, and suggest that individuals who remain medically and cognitively healthy may have slower rates of brain atrophy.