Measurement of W and Z production at $\sqrt{s}$ = 7 TeV with the ATLAS detector

In spring 2010, the LHC has delivered its first proton-proton collisions at a centre of mass of 7 TeV. The validation of the detector performance started with the measurement of some Standard Model well known processes. This paper presents the measurement of the W and Z cross section in electron and muon final states, which constitute the first sample of isolated high transverse momentum leptons. Clean signals have been extracted and the cross sections have been measured with 17 nb-1 for the W channel and about 220 nb-1 for the Z channel. All results agree with the theoretical predictions (computed at the Next to Next Leading Order) within the uncertainties equally shared between statistic, systematic and luminosity errors at the level of 10-15%.