Twenty-five male and 13 female patients with alcoholic Korsakoff’s syndrome (AKS were compared with age- and sex-matched non-Korsakoff chronic alcoholics and healthy volunteer; in a neuropsychological study, which included computer-administered tests of cognitive function The performance of male Korsakoff patients was significantly inferior to that of healthy male controls, not only in tests of memory, but also in visuo-perceptual tasks with a speed or motoi component, and on category sorting and verbal fluency measures. Compared with male alcoholics the performance of male Korsakoff patients was again inferior on similar tests. Female Korsakoff patients showed more extensive deficits compared with female controls, but differed less frorr matched female alcoholics. The results suggest that, in addition to their amnesia, many Korsakoff patients have sustainec widespread cognitive deficits, affecting particularly visuo-perceptual and abstracting functions which are sensitive to cortical lesions. The range of deficits falls short of what may be regarded a; ‘global’ in male, but probably not in female, Korsakoff’s. The implications for a dual aetiology oi AKS involving thiamine deficiency and other features associated with alcoholism, probably direci alcohol neurotoxicity, are discussed. © 1990, Cambridge University Press. All rights reserved.