SUSY search at ATLAS

The Large Hadron Collider (LHC) at CERN will be turned on in 2008. One of the major topics in LHC is supersymmetry (SUSY) search. The key point of the SUSY search is to understand the Standard Model (SM) backgrounds. Since the background estimation based on Monte Carlo has large uncertainty, we can also expect the uncertainties from detector performance especially at an early stage. We have been developing the background estimation techniques using real data5. We describe the data-driven techniques of background estimation for the SUSY search at ATLAS.