The tt production cross section and top quark mass are measured in protonproton collisions at √s = 7 TeV in a data sample corresponding to an integrated luminosity of 36 pb-1 collected by the CMS experiment. The measurements are performed in events with two leptons (electrons or muons) in the final state. Results of the cross section measurement in events with and without b-quark identi cation are obtained and combined. The measured value is σtt = 168 ± 18 (stat:) ± 14 (syst:) ± 7 (lumi:) pb, consistent with predictions from the standard model. The top quark mass mtop is reconstructed with two di erent methods, a full kinematic analysis and a matrix weighting technique. The combination yields a measurement of mtop = 175:5 ± 4:6 (stat:) ± 4:6 (syst:) GeV/c2. © SISSA 2011.