The Laboratory of Atmospheric Physics (LAP), of the Aristotle University of Thessaloniki (AUTH), Greece, in collaboration with the Koninklijk Meteorologisch Instituut (KMI) in Belgium and the Meteorological Observatory Hohenpeissenberg of the Deutscher Wetterdienst (DWD), in the framework of EUMETSAT's Satellite Application Facility on Atmospheric Composition, AC SAF, project have developed an ozone validation facility aiming to the validation of GOME-2 MetopA, MetopB and MetopC and IASI MetopA & MetopB ozone data. The facility is based on detailed comparisons of existing satellite total ozone with ground based data. The existing satellite data sets include GOME/ERS (GDP5)TOMS/EarthProbe (V8.5) and the still active OMI/Aura [OMDO3 & OMTO3]. The ground based total ozone data used as reference are available from the World Ozone and Ultraviolet Radiation Data Center (WOUDC), of the WMO Global Atmosphere Watch and from the World Ozone Mapping Centre hosted at LAP/AUTH. The Global Ozone Observing System of GAW/WMO is responsible for the collection and distribution of total ozone data a large network of ground stations, which includes Dobson, Brewer and M-124 observing stations. For the ozone profiles comparisons are of satellite ozone profiles versus quality approved ground based measurements from lidars, balloon sondes and microwave radiometers are performed.