The electrooxidation of D-sorbitol on Pt(100), Pt(110), Pt(111) and stepped surfaces vicinal to the (111) pole was studied in perchloric acid medium. The reaction is markedly influenced by the crystalline surface structure. Long range order effects of (111) terraces were also observed. Adsorbed CO (linearly, and bridge bonded to the surface, on a level which depends on the electrode surface orientation) was identified by in situ Fourier transform IR (FTIR) spectroscopy as the main poisoning species. Moreover, for Pt(111), glucono-delta-lactone and CO2 were identified as the main soluble reaction products.