The construction of the ATLAS Liquid Argon Electromagnetic Calorimeter (one barrel detector and two end-caps) has been completed and commissioning is in progress to prepare the cryostats for lowering into the ATLAS pit. After a description of the detector, its construction and readout electronics, the talk will cover results of quality checks carried out during the integration of the calorimeter wheels into the cryostats as well as selected results of its performance with particles obtained in beam tests with several series modules.