Measurements of particle production and underlying event properties with ATLAS

The measurement of production properties of mesons and baryons at sqrt(s)=7 TeV using pp collision data collected with the ATLAS experiment is presented and compared to predictions. Particle distributions sensitive to the underlying event in proton-proton collisions have also been measured with the ATLAS detector at the LHC at 7 TeV centre-of-mass energy. Various and complementary measurements are presented in the regions of each event azimuthally transverse to the hardest jet or the leading track or the Z-boson direction. When compared to the predictions of different Monte Carlo models, the data show sensitivity to modelling of the underlying event.