A　new　biocompatible　ECL　biosensor　based　on　enzyme/titanate　nanotubes/chitosan　composite　film　was　developed　for　the　determination　of　analytes　in　biological　samples.　In　the　fabrication　of　the　new　ECL　biosensor,　biocompatible　titanate　nanotubes　(TNTs)　and　a　model　enzyme,　i.e.,　choline　oxidase　(ChOX),　were　immobilized　on　a　chitosan　modified　glassy　carbon　electrode　(GCE)　via　electrostatic　adsorption　and　covalent　interaction,　respectively.　By　this　ECL　biosensor,　choline　was　enzymatically　oxidized　to　hydrogen　peroxide　and　detected　by　a　sensitive　luminol　ECL　system.　The　use　of　TNTs　not　only　provided　a　biocompatible　microenvironment　for　the　immobilized　enzyme,　which　resulted　in　an　excellent　stability　and　long　lifetime　of　the　ECL　biosensor,　but　also　exhibited　great　enhancement　towards　luminol　ECL　and　thus　led　to　a　significant　improvement　in　sensitivity　of　ECL　biosensor.　Satisfactory　results　were　obtained　when　employing　this　biosensor　in　assaying　the　total　choline　in　milk　samples.　The　work　would　provide　a　common　platform　to　develop　various　sensitive,　selective　and　biocompatible　ECL　biosensors　based　on　using　enzyme/TNTs/CHIT　composite　films.　(c)　2009　Elsevier　B.V.　All　rights　reserved.