An algorithm has been developed to retrieve totalcolumn of ozone (TCO) using MERIS TOAreflectances, which include the ozone Chappuis bands.The method assumes that the TOA reflectancespectrum in the absence of gaseous absorption can bemodelled by a third order polynomial. TCO is thenretrieved by making use of the difference between thispolynomial calculated from bands number 1, 2, 10, 12and 13, and the measured reflectance in band number3, 4, 5, 6, 7 and 8 where ozone absorbs.This method has been applied to the full MERISarchive and MERIS TCOs have been compared tothose retrieved more classically from the UV nadirsensor GOME-2A. The method is valid over bright andspectrally white surface such as snow/ice surfaces andoptically thick clouds. The TCOs from MERIS andGOME-2A agree generally well over Antarctica, whileMERIS tends to underestimate TCOs elsewhere.MERIS TCOs have also been compared to groundmeasurements and show a good correlation (bias androot mean square error of about 4 and 20 DU,respectively).