Recent years witnessed a considerable proliferation of computer-based training programmes as instruments of cognitive rehabilitation for schizophrenic patients. A study on the effects of a 3-week computer-based attention training with schizophrenic patients is presented. The Span of Apprehension and the Continuous Performance Test (CTP) were carried out before and after the training period. Performance improvements were found only on few attention training tasks. Schizophrenics had higher post-treatment hit rates on the Span of Apprehension, but no post-treatment improvements were observed in the CPT. Performance of trained patients in the external attention measures was not superior to performance of matched schizophrenic control patients. These data suggest that brief intensive computer-based attention remediation does not lead to enhanced attentional capacity in schizophrenia. Thus, it might be more adequate to teach behavioural strategies that bypass attention deficits or to offer programmes for exercising more complex cognitive skills than to try to remedy basic cognitive impairments.