To determine the prevalence of corpus callosum atrophy in chronic alcoholics and its relationship to cognitive function and brain atrophy, a prospective clinicoradiologic study was carried out in 28 right-handed male patients with chronic alcoholism and 14 age- and sex-matched right-handed control subjects. Clinical evaluation, neuropsychological testing and measurement of the midsagittal corpus callosum area and thickness (genu, truncus and splenium), as well as the frontal lobe index and the width of the cortical sulci on T1- and T2-weighted magnetic resonance images were performed. Compared to controls, alcoholics had significantly decreased corpus callosum area and thickness, mainly in the genu. Two-thirds had a corpus callosum area 2 SD below the mean of the control group. The sagittal area of the corpus callosum body correlated negatively with the degree of frontal and cortical atrophies (r = -0.5579 and -0.6853, respectively p < 0.01, both). Alcoholics with corpus callosum atrophy exhibited impairment of visual and logical memories (p < 0.05 both) and those with reduced thickness of the genu showed impairment of frontal lobe tasks (p < 0.05). The reduction of corpus callosum indices (age-corrected) also correlated with the total lifetime dose of ethanol consumed (r = 0.6107, p < 0.001), but was not related to nutritional status or electrolyte imbalance. Atrophy of the corpus callosum is common among alcoholic patients and may reflect the severity and pattern of cortical damage. The degree of this atrophy also correlated with the severity of ethanol intake.