Cognitive impairment is considered a central feature of schizophrenia. Many aspects of cognition are impaired in schizophrenia. Careful evaluation of the relationship between cognitive impairment and the other symptoms of schizophrenia has revealed several important findings. In this article, we discuss these findings, the effects of typical neuroleptic therapy on cognitive impairment, and important issues to address in cognitive enhancement studies in schizophrenia.