The influence of different ways of polishing (SiC sandpapers and diamond paste) on the electrochemical polarization behavior of commercially pure titanium rod was investigated with dc/ac electrochemical techniques and scanning electron microscopy. Contrary to the common belief that a smooth surface will give a higher corrosion resistance, the results show that in the high anodic potential range (> 2.0 V), the 1 mu m diamond paste polished electrode gave a much higher anodic current than the rough sandpaper polished ones, indicating a less protective passive film formed on the diamond paste polished electrode surface compared to that polished with the sandpaper. (c) 2005 The Electrochemical Society. All rights reserved.