An absolute sea level monitoring and altimeter calibration permanent facility is being established on the isle of Gavdos, south of the island of Crete, Greece. This calibration facility has been chosen because Gavdos is under a crossing point of the ground-tracks of TOPEX Poseidon and Jason-1, and adjacent to an ENVISAT pass. rPQate™DaicTer miSSi0nS WU1 1)6 evaluated at that si* external measurements from tide gauges. GPS, a DORIS beacon, meteorological sensors, wave height sensors, airborne campaigns for gravitv and sea surface topography, water vapor radiometry, solar atmospheric spectrometry, GPS buoys, altimeter transponder. Satellite Laser Ranging, etc. The mean sea level and the earth’s tectonic deformation field in the region will be also determined accurately. The GAVDOS project has started in December 2001 and has been in the context of an international cali¬bration validation effort of the Jason-1 Science Working Team. This paper describes the objectives, current status and future plans for the establishment of the GAVDOS calibration facility for satellite altimeter missions.