The consequences of brain abscess (BA) on cognition and behaviour have never been examined in detail. The aim of this study was to determine the long-term cognitive deficits of patients who suffered a BA and to estimate its effect on the quality of life. Twenty patients were included in the study. Follow up with neuropsychological and behavioural tests was performed 6 months to 42 years after BA (mean 10.4 ± 11.9). Cognitive deficits were defined as a test score of 2 or more standard deviations below controls’ mean in those tasks which revealed a significant group deficit. Compared with healthy age, sex and education-matched controls, 13 of 20 patients (65%) exhibited neuropsychological deficits in some cognitive tasks. Ten of those patients (50%) were significantly impaired in ≤2 cognition domains, whilst the remaining three patients (15%) showed three to five impaired domains. No correlation was found between neuropsychological impairments and patients’ age, sex, initial neurological symptoms, size and localization of BA, or secondary epileptic seizures. Reduction in quality of life was found in five patients (25%). BA may cause long lasting cognitive deficits. Despite the focal character of the lesion, long-term sequelae follow a more diffuse subcortical deficit pattern.