AbstractThe goal of the Laser MegaJoule project (LMJ), which started at CEA/DAM since 1995, is to achieve combustion of a DT (Deuterium-Tritium) target and to demonstrate a gain in energy of about 10. Target compression and the steps which leads to ignition and combustion are briefly described in order to explain the specifications of the laser driver. Laser architecture and milestones of the construction are presented.