We report a 34-year-old man who presented with alcohol-withdrawal delirium. In the early phase, diffusion-weighted MR imaging demonstrating a high intensity area in the corpus callosum, indicating Marchiafava-Bignami disease. T2-weighted MR imaging did not clearly show the lesion. He was treated and completely recovered in terms of clinical state and MRI findings. Although historically the most of Marchiafava-Bignami disease was not cured, it seems that the lesion is reversible by management in the early stage. We propose that diffusion-weighted MR imaging is useful for the early detection of Marchiafava-Bignami disease.