AbstractTwo types of titanate photoanodes are discussed, viz. mechanically polished n‐TiO2: Nb and hydrogen‐reduced n‐SrTiO3: Nb surface‐doped with LaCrO3. The anodes are investigated in acidic as well as in basic solutions. In addition the influence of ultraviolet irradiation is examined. Detailed equivalent circuits are proposed for both types of cells. Mott‐Schottky plots indicate the presence of a severely disturbed space‐charge region for both photoelectrodes. In the case of the mechanically polished n‐TiO2: Nb anode, the disturbance is attributed to surface roughness effects, whereas for the hydrogen‐reduced n‐SrTiO3: Nb, LaCrO3 anode, the existence of a nonuniform donor level is suggested.