The Large Hadron Collider will provide an opportunity to study Pb--Pb collisions at \sqrt {s_NN} = 5.5 TeV as well as other nucleus--nucleus collision systems including proton--nucleus collisions. The ATLAS apparatus with its hermetic calorimetry, a precise silicon inner detector and a background-free standalone muon spectrometer is well suited to study a wide range of phenomena in nucleus--nucleus collisions at LHC. This talk reports on the studies of the ATLAS experiment capabilities for heavy ion physics at LHC. These studies show a very good potential of the ATLAS detector for measuring global properties of nucleus--nucleus collisions such as charged particle multiplicities and azimuthal anisotropies as well as heavy quark and quarkonia production and jet quenching. The results from the first round of studies based on the full simulations of the detector response are presented. Ongoing activities are also briefly summarized.

PACS numbers: 25.75.Nq, 25.75.Dw