Fatigue　strength　of　TC4　titanium　alloy　sheet　and　its　laser　beam　and　electron　beam　welded　joints　was　investigated　experimentally.　The　median　fatigue　life　values　of　the　welded　joints,　under　various　stress　levels,　were　evaluated　by　statistic　approach.　The　effect　of　welding　condition　on　the　fatigue　life　of　the　joints　was　analyzed.　It　was　found　that　the　fatigue　life　of　the　high　density　beam　welded　joint,　under　higher　stress　levels,　was　shorter　than　that　of　the　base　metal,　however,　the　fatigue　life　of　the　high　density　beam　welded　joints　was　longer　than　that　of　the　base　metal　under　lower　stress　levels.