A search for the rare decays Bs → μ+μ− and B0 → μ+μ− performed in pp collisions at √s = 7 TeV is presented. The data sample, collected by the CMS experiment at the LHC, corresponds to an integrated luminosity of 1.14 fb−1. In both cases the number of events observed after all selection requirements is consistent with expectations from background and standard model signal predictions. The resulting upper limits on the branching fractions are BF(Bs → μ+μ−) < 1.9 × 10−8 and BF(B0 → μ+μ−) < 4.6 × 10−9 at 95% confidence level (CL). Furthermore, the combination of the results of the search for the decay Bs → μ+μ− by the CMS and LHCb experiments is presented. The combined upper limit is BF < 1.1 × 10−8 at 95% CL.