en Research Paper Research Paper The effect of titanium dioxide addition on bonding strength of CaO-P2O5 -Na 2O-TiO2glass-ceramic system was investigated as a coating on titanium substrate. Thus, different amounts of TiO2 (2, 3.5 and 5mol %) were added to the base glass batch composition. The prepared glaze slips were applied on the substrate by dip coating method, dried and then heat treated at various temperatures. After that, bonding strength of the glass- substrates was determined via shear stress testing method. The de-bonded interfaces were analyzed by scanning electron microscopy (SEM). According to these results, the 5 mol% TiO 2 containing coating showed the best bonding strength, comparing with the other coatings. The bioactivity of the coated samples was investigated by soaking them in simulated body fluid (SBF). The surface of the samples was studied using SEM and X-Ray microprobe and it was observed that an apatite layer was grown on their surface Titanium, Bioactive Coating, Bonding Strength 1 7 http://ijmse.iust.ac.ir/browse.php?a_code=A-10-127-56&slc_lang=en&sid=1 B Eftekhari Yekta Beftekhari@iust.ac.ir 180031947532846002816 180031947532846002816 Yes School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran, Iran. Sh Honarvar 180031947532846002817 180031947532846002817 No School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran, Iran.