A 42 year-old man with intraventricular haemorrhage developed a transient Korsakoff's syndrome. A small arteriovenous malformation was identified on the inner side of the left parietal lobe. Cognitive disorders are very frequent after surgery on anterior communicating artery aneurysms, more rarely when the haemorrhage interest the axial anatomic loci implicating in the process of amnesic syndromes. This case illustrates well the possibility of transient Korsakoff's syndrome after pure intraventricular haemorrhage.