The Western Alps are among the best studied collisional belts with both detailed structural mapping and also crustal geophysical investigation like ECORS and EGT seismic profiles. By contrast, the present day kinematic of the belt is still largely unknown due to small relative motions and the insufficient accuracy of the triangulation data. As a consequence, several tectonic problems still remain to solve, like the amount of N-S convergence in the Occidental Alps, the repartition of the deformation between the Alpine tectonic units, the relation between deformation and rotation across the Alpine arc. To adress these problems, the GPS ALPES group, made with french, swiss and italians research organizations has achieved the first large scale GPS surveys of the Western Alps. More than 60 sites were surveyed in 1993 and 1998 with a minimum observation of 3 days at each site. GPS data processing has been done by 3 independant teams using different softwares. The different solutions have horizontal repeatabilities (N-E) of 4-7 mm in 1993 and 2-3 mm in 1998 and compare at the 3-5 mm level in position and 2 mm/yr level in velocity. Comparing 1993 and 1998 coordinates evidences that residual velocities of the GPS marks are generally smaller than 2mm/yr, precluding a detailed tectonic interpretation of the differential motions. However, these data seem to suggest that the N-S compression of the Western Alps is quite mild (less than 2 mm/yr) compare to the global convergence between the African and Eurasian plate (6 mm/yr). This implies that the shortening must be accomodated elsewhere by the deformation of the Maghrebids or by rotations of Mediterranean microplates. Also, E-W velocity components analysis supports the idea that E-W extension might exist as already suggested by seismologic and sismotectonic data interpretation.