Effect of a fluorinated surfactant, F(CF(CF3)CF 2O)3CF(CF3)COO(CH2CH 2O)CH3, in pore structure and grain size of the TiO 2 films deposited cathodically was studied. Increase in pore size and decrease in grain size were observed when the fluorinated surfactant was used. When supercritical CO2 was introduced into the system, synergetic effect on increasing the pore size was observed. Also, grain coarsening was observed for the films deposited with supercritical CO2. Therefore, the fluorinated surfactant combining with supercritical CO2 demonstrated the ability to control morphology and grain size of the deposited TiO2 films at the same time.