ATLAS B-physics performance

We review the ATLAS B-physics program to be performed at the LHC collider at CERN. By exploiting a multi-purpose detector and a flexible triggering system, the ATLAS Collaboration expects to take full advantage of the large LHC bb̄ cross section, especially during the first years of low-luminosity running. Simulation results are presented here for some of these studies, with particular focus on CP-violation results, Bs mixing and rare leptonic decays of B mesons.