The ATLAS detector at LHC has been designed to cover a large physics program having, as main goal, the understanding of the origin of the EW symmetry breaking.
Muon signatures are one of the basic tools to trigger, select and measure final states involved in SM precision measurement and searches.
In this seminar the commissioning of the muon signatures in ATLAS is described giving emphasis to the complementarity of the inner tracking system and the large muon spectrometer.
The commissioning of the muons system based at first on a large samples of cosmic rays collected in 2008 and 2009, are presented.
With first collision events the access to benchmark processes like the J/psi and Z has given the possibility to largely improve the performance of muon trigger and reconstruction.
The impact of these studies on muon performance is reported.
A (biased) selection of physics results published by ATLAS on final states with muons are also presented.