It is not uncommon that congenital anomalies cause symptoms only in ad ult life, without any apparent reason. We experiened one case of biliary ectasia due to aberrant hepatic artery compression confjrmed by pre Op. study and operation. We discussed in this paper variation of hepatic artery branching pattern and its common duct crossing pattern and then, We concluded that aberrant hepatic artery compression is one of anomalous etio logic factor of adult life biliary ectasia and its precipating factor is probably artheroscl erotic changes and local inflammation. In our case, Ascending hepatitis indicated that there was biliary stasis for a longer duration prior to appearance of jaundice.