Zr-doped SrTiO3 was used as a photoanode in a three-electrode electrochemical cell. The three organic dyes Safranin, Fluorescein and Eriochrome black T were used as sensitizers in the cell. The results showed that applying the dyes in photoelectrochemical solar (PECS) cells increased the solar efficiency to 2-3 times its value without dyes. The efficiency reaches its maximum value when the dye concentration is sufficient to cover the surface of the semiconductor electrode with a continuous monolayer. Dye concentration higher than this value resulted in a decrease of the efficiency. Mott-Schottky plots gave a doping density of 1.34 x 10(16) cm(-3) for the sample and a space charge width of 1.5-2.0 x 10(-6)cm (pH dependent). H-2 was produced at zero bias in the presence of Safranin dye at a light intensity of 25 mW/cm(2) with an efficiency of about 39%. Both H-2 and O-2 were produced in the stiochiometric ratio. Cyclic voltammetry (c.v.) measurements showed two cathodic current peaks revealing two reduction processes at the semiconductor electrode.