Tetralogy　of　Fallot　(TOF)　is　one　of　the　most　common　complex　congenital　heart　diseases　of　newborns.　In　the　presence　of　TOF,　it　is　vital　that　creation　of　a　shunt　between　the　pulmonary　and　systemic　circulations.　The　objective　of　this　study　is　to　use　computational　fluid　dynamics　(CFD)　approaches　to　simulate　flow　variations　in　patients　of　TOF　before　and　after　the　operation.　Knowledge　of　the　flow　conditions　may　be　helpful　in　the　clinical　management　of　these　patients,　whose　survival　is　critically　dependent　on　the　blood　flow　distribution　between　the　pulmonary　and　systemic　circulations.