W and Z studies at CMS

The production of $W$ and $Z$ bosons has been observed in pp collisions at a center-of-mass energy of $7$ and $8$ TeV using data collected in the CMS experiment. $W$ events were selected containing an isolated, energetic electron or muon. $Z$ events were selected containing a pair of isolated, energetic electrons or muons. Data-driven methods are used to estimate reconstruction and triggering efficiencies, and well as the main backgrounds. We present the $W$ and $Z$ signal yields and the extracted cross-sections at $\sqrt s=8$ TeV. We discuss the measurements of the lepton charge asymmetry in the reconstructed $W$ events decaying to a lepton and a neutrino, obtained in the electron and muon decay channels at $\sqrt s=7$ TeV. We also report on the measurements of the differential cross section, forward-backward asymmetry and electroweak couplings of events coming from the Drell-Yan process at $\sqrt s=7$ TeV.