In this study, we aimed to determine the progression of brain atrophy in the parkinson variant of multiple system atrophy (MSA-P). Voxel-based morphometry was applied to two consecutive high resolution MR images of 14 patients with probable MSA-P in comparison to 14 patients with Parkinson's disease (PD). The time interval between baseline and follow-up investigations (1.0 +/- 0.5 SD years in MSAP and 1.4 +/- 0.6 SD years in PD patients) was introduced as covariate in the statistical analysis. Additionally, correlation analyses were performed between the progression maps and clinical data. We observed marked progression of brain atrophy in the MSA-P cohort, the regions including striatum, mesencephalon, thalamus and cerebellum, but also cortical regions such as the primary sensorimotor cortex, supplementary motor area, lateral premotor cortex, medial frontal gyrus, middle frontal gyrus, orbito-frontal cortex,insula, posterior parietal cortex and hippocampus. Short disease duration was correlated with progression of atrophy in the striatum whereas longer disease duration was correlated with increasing atrophy in the cortical areas and cerebellar hemispheres. The UPDRS-III score was not significantly correlated with any brain region. Our data suggest that cortical atrophy is prominent in MSA-P and early degeneration of the basal ganglia drives late onset cortical atrophy.