We report a single-case study of a patient suffering from Marchiafava-Bignami disease (MBD), a rarely intra vitam diagnosed syndrome with focal demyelination in the corpus callosum, which is usually found in patients with chronic alcohol abuse. Our study explored a variety of motor, sensory and visual functions. Striking features were left apraxia caused by two lesions in the rostral area, and left hemidyslexia related to a large splenial lesion demonstrated by MRI. As symptoms of disconnection may remain undetected clinically, MRI is a most useful tool for the diagnosis of MBD.