Poly(ethylene　glycol)　(PEG)/SiO　2-CaO-P　2O　5　hybrid　xerogels　were　prepared　using　a　room　temperature　sol-gel　process.　The　advantage　of　this　hybrid　material　over　conventional　composites　is　the　molecular　scale　interactions　between　the　bioactive　inorganic　components　and　the　biodegradable　organic　components.　Since　PEG　was　added　into　the　sol　when　the　hydrolysis　of　tetraethoxysilane　occurred,　the　molecular　chain　of　PEG　was　penetrated　into　the　SiO　2　networks　to　form　a　semi-IPN　structure.　Due　to　the　excellent　biocompatibility　and　aqueous　solubility　of　PEG　molecules,　as　well　as　the　bioactivity　of　the　inorganic　components,　the　biological　and　mechanical　properties　of　this　hybrid　xerogel　exhibit　great　potential　for　bone　regeneration　applications.　The　formation　of　hydroxyapatite　was　observed　when　the　xerogel　was　immersed　into　simulated　body　fluid,　demonstrating　good　bioactivity　of　the　hybrid.　The　cell　toxicity　test　also　demonstrated　that　the　hybrid　material　is　suitable　for　the　proliferation　of　MC3T3-E1　cells.　Thus,　the　PEG/SiO　2-CaO-P　2O　5　hybrid　xerogel　has　great　potential　to　meet　the　demands　of　bone　regeneration　materials.　©　2012　Elsevier　B.V.　All　rights　reserved.