To assess the frequency allele and genotypic distribution of polymorphism rs165599 in catechol-O-methyltransferase in Kinh ethnic-patients with schizophrenia. Subjects and methods: A case-control study consisted of 227 schizophrenic patients and 92 healthy controls in the Kinh ethnic. The rs165599 was genotyped by PCR-RFLP and statistical analysis was performed by Chi-Square test. Results: The frequency of allele A and G in schizophrenic patients were and , respectively. The frequency of allele A and G in healthy controls were and , respectively (p > ). In terms of distribution of AA genotype, the rate was (patients) and (controls). In terms of distribution of AG and GG genotype in schizophrenic patients and healthy controls were respectively: AG (, ); GG (, ) (p > ). Conclusion: There was no correlation among the frequency of allele, genotypic distribution of polymorphism rs165599 and schizophrenia in the Kinh ethnic. | Polymorphism characteristics of RS165599 in COMT gene in schizophrenia patients in Kinh population