Magnetic resonance imaging (MRI) studies showed a link between chronic smoking and structural brain abnormalities. To date, little is known about the long-term effects of smoking on gray matter deficiencies. MRI study was carried for 44 smokers and 44 matched non-smokers to assess gray matter volume differences between the two groups. Decreased gray matter volumes were found in left thalamus, medial frontal cortex and anterior cingulate of smokers in comparison to controls. This voxel-based morphometry study is showing reduction of regional gray matter volume in smokers, which might better guide future research into the pathogenesis of chronic smoking.