The hardness, wettability, and electrochemical properties of Ti6Al4V alloy surfaces treated with anodic oxidation and plasma oxidation as well as the viabilities of the different cell lines on the obtained surfaces were investigated. The anodic oxidation was performed for 10 min under 100 V potential, and it resulted in a 0.95 mu m thick nanoporous anatase-TiO(2)structure. On the other hand, plasma oxidation was carried out at 650 degrees C for 1 h and resulted in a dense rutile-TiO(2)structure with a thickness of 1.2 mu m. While a hardness of HV(0.025)823 and roughness of similar to 220 nm were obtained by plasma oxidation, those obtained by anodic oxidation were HV(0.025)512 and similar to 130 nm, respectively. The anodic oxidation process created a more hydrophilic surface with a contact angle of 87.2 degrees. Both oxidation processes produced similar properties in terms of corrosion behavior and showed better resistance than the as-received state in a certain range of potential. Moreover, the surface treatments led to no significant change in the protein adsorption levels, which indicates that the difference in viability between the osteoblast and fibroblast cells was not due to the difference in surface protein adsorption. Given all the factors, the surfaces obtained by anodic oxidation treatment revealed higher cell viability than those obtained by plasma oxidation (p= 0.05).