e, mu, tau commissioning/cosmic CMS

The cosmic data collected in 2008 and 2009 have been invaluable to study the performance of the CMS detector, to commission the alignment and calibration techniques, test the muon identification algorithms and to make several cosmic ray measurements. This contribution focus on the commissioning of the lepton reconstruction and identification algorithms, mainly showing the muon reconstruction performance evaluated using the large cosmic data sample. Although direct tests of the tau and electron identification algorithms were not possible using cosmic rays, indirect information on their commissioning status can be inferred looking at the detector performance, of which a summary is given here.