involved in metabolizing the monoamine, are associated with the onset of bipolar disorder or the clinical variables such as suicide attempt during illness, age of onset and family history. This study investigated the genotype or allele frequency of COMT and MAOA genes in bipolar disorder patients and compared the results to those of healthy controls. Method:We collected the blood of 184 bipolar patients and 216 healthy controls. COMT Val158Met and MAOA EcoRV/C1460T were genotyped. T-test, analysis of variance, chi-square test and Fisher’s exact test were used. Results:There was no significant association between COMT Val158Met and MAOA EcoRV/C1460T and onset of bipolar disorder. In the bipolar patients group, there was no significant association between COMT Val158Met and MAOA EcoRV/C1460T and clinical variables such as suicidal attempt during illness, family history and age of onset. Conclusion:The present findings indicate that there is no association between COMT Val158Met and MAOA EcoRV/C1460T and onset of bipolar disorder or clinical variables such as suicidal attempt during illness, age of onset and family history.