Excellent electron and photon reconstruction and identification capability will be needed over a broad energy range for most physics studies with the ATLAS detector at the Large Hadron Collider (LHC). Events with electrons and photons in the final state are important signatures to rediscover many of the Standard Model (SM) processes (electroweak vector bosons, top quarks, etc.), to search for new physics beyond the SM (new resonances at TeV scale, SUSY, etc.), to discover of Higgs boson (H→4e, H→γγ) and to understand of detector performance and its calibration. This paper describes the overall ATLAS detector performance for the reconstruction and identification of photons and electrons over a wide range of transverse energies, spanning from a few GeV to 5TeV.