A bstract The $ \mathrm{t}\overline{\mathrm{t}} $ production cross section $ \left( {{\sigma_{{\mathrm{t}\overline{\mathrm{t}}}}}} \right) $ is measured in proton-proton collisions at $ \sqrt{s}=7 $ TeV in data collected by the CMS experiment, corresponding to an integrated luminosity of 2.3 fb −1 . The measurement is performed in events with two leptons (electrons or muons) in the final state, at least two jets identified as jets originating from b quarks, and the presence of an imbalance in transverse momentum. The measured value of $ {\sigma_{{\mathrm{t}\overline{\mathrm{t}}}}} $ for a top-quark mass of 172.5 GeV is $ 161.9\pm 2.5\left( {\mathrm{stat}.} \right)_{-5.0}^{+5.1}\left( {\mathrm{syst}.} \right)\pm 3.6\,\left( {\mathrm{lumi}.} \right)\,\mathrm{pb} $ , consistent with the prediction of the standard model.