Objective:Recently, many experimental evidences have been reported that psychiatric diseases are closely related with neurodevelopmental abnormalities and this can be properly explained by apoptosis. It is known that Apo-1/Fas is one of the genes in charge of apoptosis related with neurodevelopmental abnormalities. In this study, the association between bipolar disorder and functional polymorphism in Apo-1/Fas promoter gene has been investigated. Method:For 81 bipolar disorder patients and 217 healthy control subjects, MvaI restriction fragment length polymorphism(RFLP) of Apo-1/Fas promoter gene was analyzed after polymerase chain reaction(PCR) amplification. Result:There was a statistical significant difference in genotypic distribution(${chi}^2$=16.656, df=2, p=0.0002) and allelic frequencies(${chi}^2$=14.225, df=1, p=0.0002) between bipolar disorder patients and healthy control subjects. Conclusion:Our results suggest an association between functional polymorphism in Apo-1/Fas promoter gene and bipolar disorder and provide the important genetic information related with the pathogenesis of the disease. Further studies employing larger samples are required to clarify the present results.