ATLAS Detector Commissioning

ATLAS is a general purpose detector installed at the Large Hadron Collider at CERN. It's in the final commissioning phase, in preparation for the first LHC physics run. In this talk the status of the ATLAS sub-detectors (Inner Detector, Calorimeter and Muon Spectrometer) and of the trigger system will be reviewed. The results of the long cosmics run taken in 2008 and of the first experience with beam operation will be analyzed. Finally, the activity planned during the winter shutdown and the preparation for the 2009 data taking will be illustrated.