Using magnetic resonance imaging (MRI), we measured in patients with multiple sclerosis (MS) the brain volume changes over a one year period and correlated them with changes in disability. Three-dimensional T1-weighted magnetization prepared rapid acquisition gradient-echo (MP-RAGE) (with subsequent reconstruction of 1-mm thick axial slices) scans of the brain were obtained at baseline and after one year from 14 MS patients. The average percentage decrease of total brain volume was ten times higher for patients who had a deterioration in their expanded disability status scale (EDSS) scores than for those who had not (mean percentage changes were -4.7 and -0.4%, respectively). Over a short time follow-up period, the decrease of brain volume was higher in the MS patients with clinical evolution compared to those with unchanged disability.