  We present BAX, Base de Donn\'ees amas de galaxies X
(http://webast.ast.obs-mip.fr/bax), a project aiming at building a
comprehensive database dedicated to X-rays clusters of galaxies allowing
detailed information retrieval. BAX provides the user with {\it basic data}
published in the literature on X-rays clusters of galaxies as well as with
information concerning the physical properties in the X-rays domain or at other
wavelengths. BAX allows individual studies on selected clusters as well as
building up homogenous samples, from known X-rays clusters for which selection
criteria are chosen through web interfaces. We expect BAX to become a useful
tool for astronomy community in order to optimize the cluster science return
using data from both ground based facilities like MEGACAM (CFHT), VIRMOS (VLT)
and space missions like XMM, Chandra and Planck.
