Brain ERPs were recorded in ten unmedicated schizophrenic patients and age- and sex-matched healthy controls during a multidimensional listening task. Patients showed a marked reduction in a long-duration attention-related negative ERP component, termed 'processing negativity' (PN), which was elicited by attended stimuli. The amplitude of PN was significantly correlated with SANS and SAPS scores of schizophrenic symptoms. The P300 component was also reduced in amplitude in patients, and was significantly correlated with SANS ratings of negative thought disorder. These findings provide neurophysiological evidence of impairment in the maintenance of selective attention and the cognitive processes associated with target detection among schizophrenic patients. The reduced PN in schizophrenics implicates frontostriatal pathways in the aetiology of attentional deficits in schizophrenia.