Objectives To assess radiographic brain abnormalities and investigate volumetric differences in adults born preterm at very low birth weight (VLBW; < 1500 g), using siblings as controls. Study design We recruited 79 adult same-sex sibling pairs with one born preterm at VLBW and the sibling at term. We acquired three Tesla brain MRIs from the 78 preterm subjects and 72 siblings. A neuroradiologist, masked to participants’ prematurity status, reviewed the images for parenchymal and structural abnormalities, and FreeSurfer software 6.0 was used to conduct volumetric analyses. Data were analyzed by linear mixed models. Results We found more structural abnormalities in VLBW subjects than in siblings, 37% vs. 13%. The most common finding was periventricular leukomalacia, present in 15% of VLBW subjects and in 3% of siblings. The VLBW group had smaller absolute brain volumes (-0.4 SD) and, after adjusting for estimated intracranial volume, less gray matter (-0.2 SD), larger ventricles (1.5 SD), smaller thalami (-0.6 SD), caudate nuclei (-0.4 SD), right hippocampus (-0.4 SD) and left pallidum (-0.3 SD). We saw no volume differences in total white matter (-0.04 SD, 95% CI -0.13, 0.09). Conclusion Preterm VLBW adults had a higher prevalence of brain abnormalities than their termborn siblings. They also had smaller absolute brain volumes, less gray but not white matter and smaller volumes in several gray matter structures.