ATLAS ID performance at LHC

Since the LHC startup in 2009, the ATLAS inner tracker has played a central role in many ATLAS physics analyses. Rapid improvements in the calibration and alignment of the detector allowed it to reach nearly the nominal performance in the timespan of a few months. The tracking performance proved to be stable as the LHC luminosity increased by five orders of magnitude during the 2010 proton run, while the performance was only slightly degraded in the extremely dense heavy ion collisions. New developments in the offline reconstruction for the 2011 run will improve the tracking performance in high pile-up conditions, as well as in highly boosted jets.