  We have investigated the abundance of several chemical elements in two large
stellar samples kinematically representative of the thin and the thick disks of
the Galaxy. Chemical, kinematical and age data have been collected from high
quality sources in the literature. Velocities (U,V,W) have been computed and
used to select stars with the highest probability to belong to the thin disk
and the thick disk respectively. Our results show that the two disks are
chemically well separated. Both exhibit a decline of [$\alpha$/Fe] with
increasing [Fe/H]. A transition between the thin/thick disks stars is observed
at 10 Gyr.
