Central nervous system involvement was evaluated in 36 patients with systemic lupus erythematosus (SLE) using cerebral computed tomography (CT), electroencephalography (EEG), and a neuropsychological test battery. The purpose was to investigate whether brain dysfunction as assessed by comprehensive neuropsychological investigation is associated with findings of routine investigation methods such as CT and EEG which are available in most hospitals. Abnormal EEG was found in 19%, and CT revealed cerebral atrophy in 47% of SLE patients. Few neuropsychological functions were affected by the presence of abnormal EEG, cerebral atrophy, or infarcts. Significant associations were found only between cortical atrophy and impairment of tactile spatial problem-solving and motor dexterity, and between cortical infarcts and motor dexterity in the dominant hand. The value of conventional EEG in assessing cerebral SLE is negligible, except for identifying epileptic activity and focal pathology. Cerebral CT has little relevance in predicting brain dysfunction as established by neuropsychological assessment in SLE, except for detecting cortical atrophy and infarcts.