An advanced operational algorithm has been developed for the routine calibration of the Meteosat radiometer solar channel. The calibration method relies on calculated radiances over bright desert sites whereas ocean targets are used for consistency checks. Calibration errors are estimated accounting for the uncertainties of both the sensor spectral response characterization and target property description. This algorithm has been used to systematically calibrate Meteosat-5 and -7 observations. Results show that it is possible to calibrate the visible band with an estimated accuracy of about 6% when the sensor response characterization is reliable and to monitor the sensor long-term drift. These results are confirmed by Clouds and the Earth's Radiant Energy System observations