Recent QCD studies performed within ATLAS will be shown. QCD generators have been tuned in order to have a good description of the available minimum bias and underlying event data. Their predictions at the LHC energy and the reconstruction of events in ATLAS have also been studied. Jet physics analysis has been performed as well: to study how a measurement of the inclusive jet cross section could help on constraining parton density functions, how well dijet azimuthal decorrelations can be measured and how to use multi-jet events to calibrate the detector.

PACS numbers: 13.85.Hd, 13.87.--a