The purpose of this study was to compare the effect of clozapine and haloperidol on cerebral asymmetry of visual recognition in 10 right-handed healthy male volunteers. The visual-hemifield take perfomance was applied to each subject after the oral administration of either a placebo. Or haloperidol (3mg). Or clozapine (50mg). Respectively. Stimuli were 12 one-letter Hangul words. 12 two-letter Hangul words. 12 one-letter Chinese words and 12 two-letter Chinese words. Using a computer program and a computer monitor. All subjects were tachistoscopically presented to the location. 30° distant from fixation point in either of the right or left visual field for 150msec. Each subject was instructed to respond by reading the words immediately upon the recognition of them. The procedure was automatically controlled by computer program. Sequence of presentation was randomized. The reaction time and the correct response rate were measured and analized. It was no significant difference in cerebral asymmetry of correct response rate and reaction time among clozapine. Haloperidol. And placebo. These data suggest that single oral administration of clozapine and haloperidol dose not change the cerebral asymmetry of visual recognition. But multiple dose study is further recommended.