Undoped Nanostructured Titanium Dioxide thin film (UN) and Cobalt doped nanostructured (CoDN) TiO2 thin film has successfully prepared using sol-gel method and deposited onto silicon and glass substrate by spin coating technique. Nanostructured TiO2 thin film were prepared at 0.1 M, 0.2 M, 0.3 M and 0.4 M, Co doped TiO2 thin film was prepared with additional of ion Co at 1 at%. The electrical and optical properties of the UN TiO2 thin films and CoDN TiO2 thin film has successfully studied. The electrical properties indicates that both 0.2 M of UN TiO2 thin film and CoDN TiO2 thin film gives low of resistance compare to other sol-gel concentration. As we compared both UN TiO2 thin film and CoDN TiO2 thin film, the lowest resistance comes from Cobalt doped TiO2 thin film. For optical properties, CoDN TiO2 thin film gives the highest percentage of transmittance, which is above 80% in visible region (450-1000 nm). As for band gap energy, there is decreasing in band gap energy compared from UN TiO2 thin film to CoDN TiO2 thin film.