ATLAS is a general purpose experiment which will operate at the LHC. In the main focus of ATLAS is the investigation of the nature of the electroweak symmetry breaking, and therefore the search for the Higgs boson. Electrons, photons, muons, tau and b-jets are important components of the possible physics signatures expected. The expected quality of particle-ID impose strong requirements upon the performance of the detector, which has to be sensitive to the Higgs boson discovery over the full range of allowed masses. In this paper the detector performance in terms of particle identification is presented.

PACS numbers: 14.80.Bn, 14.80.Cp, 07.05.Kf, 07.05.Tp