Aim:　To　improve　the　antibacterial　and　mammalian　cell　compatibility　properties　of　titania　nanotubes　(TNTs)　anodized　into　titanium　(Ti).　Materials　&　methods:　3-8-nm　TiO2　nanoparticles　were　decorated　on　the　surface　and　inside　TNT　(TNT-TiO2)　through　a　hydrothermal　method.　After　UV　light　treatment,　two　types　of　oral　bacteria　and　stem　cells　were　cultured　on　the　samples　to　determine　antibacterial　and　compatibility　properties.　Results:　TiO2　nanoparticles　increased　the　surface　area　and　photocatalysis　of　TNTs.　Based　on　the　photocatalysis　effect　and　prolonged　photo-induced　wettability,　the　numbers　of　Streptococcus　mutans　and　Porphyromonas　gingivalis　were　lower　on　the　surface　of　TNT-TiO2　than　pure　Ti　and　TNTs　after　the　first　7　days.　Specifically,　for　S.　mutans,　the　glycosytransferase　(gtf)　genes　were　downregulated　0.1-0.2-fold　on　TNT-TiO2.　Due　to　the　different　topography　and　high　surface　energy　of　TNT-TiO2,　stem　cells　also　showed　improved　osteogenic　functions　on　TNT-TiO2.　Conclusion:　In　this　study,　we　demonstrated　for　the　first　time　improved　antibacterial　properties　and,　at　the　same　time,　greater　stem　cell　osteogenic　capacity　when　decorating　TNTs　with　nanosized　TiO2　particles,　which　may　significantly　improve　orthopedic　and　dental　implant　efficacy.