Résumé : A search for the standard model Higgs boson in the H → ZZ → 2ℓ2ν decay channel, where ℓ = e or μ, in pp collisions at a center-of-mass energy of 7TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 fb -1. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440GeV range is excluded at 95% confidence level.