The biological studies related to the diameter of TiO₂ nanotube have mainly focused on the biocompatibility and functionality of cells. The purpose of this study was to evaluate the size effect of various TiO₂ nanotube diameters on inflammatory responses such as the generation of iNOS, NO and interleukin-1β(IL-1β), and tumor necrosis factor-α(TNF-α) in LPS-stimulated Raw 264.7 macrophages. The adhesion and proliferation of macrophages cultured on 100 nm Ti02 nanotube were significantly higher than those cultured on Ti(P (0.05). The results of nitric oxide(NO) generation from macrophage indicated that the value of 30 and 100 ㎚ TiO₂ nanotube had the tendency of reduction and increment, respectively, compared to Ti control group(P>0.05). The mRNA expression of iNOS, IL-1β and TNF-α resulted that the IL-1β (the degree of inflammation response) values of 30 ㎚ TiO₂ nanotube was significantly lower than those of Ti(P<0.05). In additions, IL-1β values of 100 ㎚ TiO₂ nanotube was significantly higher than those of Ti(P<0.05) Thus, it was concluded that TiO₂ nanotube did not have cytotoxicity effect on RAW 264.7 macrophage, but 100 ㎚ TiO₂ nanotube had the potential for accelerating inflammation response in Raw 264.7 macrophages. Further investigation is required to resolve detailed mechanisms relating to the morphology and nanostructure of TiO₂ nanotube and inflammation response.