The Milky Way harbours two disks that appear distinct concerning scale-heights, kinematics, and elemental abundance patterns. Recent years have seen a surge of studies of the elemental abundance trends in the disks using high resolution spectroscopy. Here I will review and discuss the currently available data. Special focus will also be put on how we define stars to be members of either disk, and how current models of galaxy formation favour that thick disks are formed from several accreted bodies. The ability for the stellar abundance trends to test such predictions are discussed.

Review article presented at the ESO-ARCETRI workshop on: Chemical Abundances and Mixing in Stars in the Milky Way and its Satellites (September 13-17 2004), To be published in "ESO Astrophysics Symposia", Editors: Luca Pasquini and Sofia Randich, 6 pages, 4 figures (one in colour)