We investigated effects of conjugate bases as surface modifiers on the photovoltage of dye-sensitized solar cells (DSSCs). TiO2 films were soaked in aqueous solutions containing PO43-, CO32- and C2O42- ions to prepare Ph-TiO2/FTO, Ca-TiO2/FTO and Ox-TiO2/FTO electrodes, respectively. For a reference cell, Wa-TiO2/FTO electrode treated with pure water (H2O) was also prepared. With increasing basicity of the surface modifiers, open circuit voltage (V-oc) of DSSCs with the surface-modified photoelectrodes was improved in the order of Ph-TiO2/FTO approximate to Ca-TiO2/FTO > Ox-TiO2/FTO > Wa-TiO2/FTO. Dark current measurements revealed that the enhancements in V-oc were attributed to a negative shift of conduction band edge of TiO2 by base treatment such as PO43-, CO32- and C2O42-.