['This study investigated whether the catechol-O-methyltransferase (COMT) gene V158M single-nucleotide polymorphism (SNP) influences susceptibility to tardive dyskinesia (TD).', 'We examined 209 Korean schizophrenic patients using the Abnormal Involuntary Movement Scale (AIMS), with genotyping performed for the COMT gene V158M SNP.', 'The logistic regression analysis showed that old age [p = 0.032, OR = 1.40 (OR corresponds to 10-year), 95% CI = 1.03-1.90] was a risk factor for TD, but there was no significant association between the COMT genotype and TD. The heterozygotes (MV genotype) of the COMT gene polymorphism tended to develop TD less than homozygotes (MM and VV); however, the risk did not reach statistical significance (p = 0.050, OR = 1.81, 95% CI = 1.00-3.29).'] Is val158Met polymorphism in the catechol-O-methyltransferase ( COMT ) gene associated with tardive dyskinesia in schizophrenia?