There was performed clinical and neurophysiological observation of 41 patients with arteriovenous malformations (AVM) of gyrus cinguli. Disorders of memory appeared to be the main manifestations before the operation in 38 patients, moreover they had the features of Korsakov's syndrome in 5 patients. Autonomic and epileptic-like fits weren't quite characteristic. Memory impairment was observed in 23 from 38 patients after operation, however there weren't found any qualitatively new disorders. The first appearance of Korsakov's syndrome after operation was found in 3 patients. The degree of the increase of memory impairment correlated with the degree of the destruction of the gyrus cinguli as well as with the massivity of AVM passing into corpus callosum. Qualitative analysis of amnestic syndromes revealed that practically all the patients had the alteration of the selectivity of the memory traces, inability to keep in mind the meaning of the tale. It was accompanied by an absence of criticism toward patients' own defects. Similar signs of disorders had close resemblance with amnestic defects of the patients with frontal damages. That testified the significance of both damages of frontal lobes and their connections in formation of clinical pattern in human.