The　present　study　designs　and　prepares　Ni-free　Zr60　+　xTi2.5Al10Fe12.5　-　xCu10Ag5　(at.%,　x　=　0,　2.5,　5)　bulk　metallic　glasses　(BMGs)　by　copper　mold　casting　for　potential　biomedical　application.　The　effects　of　Zr　content　on　the　in　vitro　biocompatibility　of　the　Zr-based　BMGs　are　evaluated　by　investigating　mechanical　properties,　bio-corrosion　behavior,　and　cellular　responses.　It　is　found　that　increasing　the　content　of　Zr　is　favorable　for　the　mechanical　compatibility　with　a　combination　of　low　Young＇s　modulus,　large　plasticity,　and　high　notch　toughness.　Electrochemical　measurements　demonstrate　that　the　Zr-based　BMGs　are　corrosion　resistant　in　a　phosphate　buffered　saline　solution.　The　bio-corrosion　resistance　of　BMGs　is　improved　with　the　increase　in　Zr　content,　which　is　attributed　to　the　enrichment　in　Zr　and　decrease　in　Al　concentration　in　the　surface　passive　film　of　alloys.　Regular　cell　responses　of　mouse　MC3T3-E1　cells,　including　cell　adhesion　and　proliferation,　are　observed　on　the　Zr-Ti-Al-Fe-Cu-Ag　BMGs,　which　reveals　their　general　biosafety.　The　high-Zr-based　BMGs　exhibit　a　higher　cell　proliferation　activity　in　comparison　with　that　of　pure　Zr　and　Ti-6Al-4V　alloy.　The　effects　of　Zr　content　on　the　in　vitro　biocompatibility　can　be　used　to　guide　the　future　design　of　biocompatible　Zr-based　BMGs.　©　2014　Elsevier　B.V.　All　rights　reserved.