It is not uncommon that congenital anomalies cause symptoms only in adult life, without any apparent reason. We experiened one case of biliary ectasia dut to abrrant hepatic artery compression confirmed 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 etiologic factor of adult life biliary ectasla and its precipating factor is probably artherosclerotic changes and local inflammation. In our case, Ascending hepatitis indicated that there was biliary stasis for a longer duration prior to appearance of jaundice.