Recent　efforts　are　being　conducted　to　develop　alternative　asphalt　binders　from　various　bio-mass　resources　for　future　flexible　pavements　construction　due　to　their　renewability　and　the　increasing　costs　of　conventional　petroleum-based　asphalt.　The　objective　of　this　paper　is　to　investigate　the　potential　of　using　the　waste　cooking　oil　(WCO)　based　bio-oil　as　a　modifier　for　petroleum　based　neat　asphalt　binder　and　Styrene-Butadiene-Styrene　(SBS)　modified　binder　by　means　of　chemical　and　rheological　approaches.　A　series　of　tests　were　conducted　for　such　purpose,　including　the　infrared　spectroscopy　test,　frequency　sweep　rheological　test,　multiple　stress　creep　recovery　test,　and　linear　amplitude　sweep　test.　The　infrared　spectroscopy　results　indicate　identical　chemical　functional　groups　between　the　bio-oil　and　the　petroleum　asphalt　binder　though　acid,　ether,　ester　and　alcohol　compounds　were　also　observed　within　the　bio-oil.　The　bio-oil　modified　binders　display　increased　carbonyl　index　with　increasing　the　bio-oil　percent　weight　whereas　the　sulfoxide　index　almost　exhibits　the　same　level　as　that　of　the　control　asphalt.　Frequency　sweep　tests　show　that　the　bio-oil　addition　obviously　decreased　the　binder　stiffness　according　to　the　dynamic　shear　modulus　master　curve.　Due　to　this　softening　effect　from　the　bio-oil　modifier,　the　weakened　rutting　resistance　of　bio-binders　are　demonstrated　for　both　neat　and　SBS　binders　at　the　high　temperature　range.　The　fatigue　life　of　bio-binders　at　intermediate　temperature　under　cyclic　fatigue　loading　are　found　to　be　significantly　improved　by　increasing　bio-oil　content　but　the　binder　yield　energy　simultaneously　decreased.　It　can　be　preliminarily　concluded　that　the　WCO　based　bio-oil　tested　in　this　study　could　be　used　as　a　potential　bio-modifier　to　produce　a　sustainable　asphalt　binder.　(C)　2018　Elsevier　Ltd.　All　rights　reserved.