Serial CT and MR imaging findings in a 44-year-old woman with Marchiafava-Bignami disease (MBD) are reported. In the acute stage, CT studies disclosed subtle hypodensity in the splenium, and T2-weighted MR images revealed apparent high signal intensity of the splenium and the central portion of the corpus callosum. Treatment with vitamin B complex resulted in complete recovery. T2-weighted MR images obtained three weeks after admission revealed dramatic resolution of imaging abnormalities, with only faint high signal intensity remaining in the splenium. The sequential changes observed on CT and MR images provided early diagnosis of MBD and the resolution of the lesion considered as brain edema, which suggested that edema might, in addition to demyelination or necrosis, be involved in the acute progression of MBD.