TiC has been used as a counter electrode catalyst in place of Pt for triiodide redn. in dye-sensitized solar cells. Its catalytic activity can be comparable to that of Pt. The effect of the thickness of the TiC layer on the performance of the dye-sensitized solar cells was investigated by electrochem. impedance spectroscopy, cyclic voltammetry, and Tafel polarization measurements. We found that as the film thickness increased, the fill factor and short-circuit c.d. increased, which led to improved power conversion efficiency. When the TiC film was thicker than 20 μm, however, no significant continuous improvement in the catalytic activity was obsd. A high power conversion efficiency of 6.46% was obtained for the dye-sensitized solar cell by using a TiC counter electrode at the optimized film thickness, a value similar to that obtained with a Pt counter electrode.