A search for a doubly-charged Higgs boson in pp collisions at √s=7 TeV is presented. The data correspond to an integrated luminosity of 4. 9 fb -1 , collected by the CMS experiment at the LHC. The search is performed using events with three or more isolated charged leptons of any flavor, giving sensitivity to the decays of pair-produced triplet components Φ ++ Φ -- , and Φ ++ Φ - from associated production. No excess is observed compared to the background prediction, and upper limits at the 95 % confidence level are set on the Φ ++ production cross section, under specific assumptions on its branching fractions. Lower bounds on the Φ ++ mass are reported, providing significantly more stringent constraints than previously published limits. © 2012 CERN for the benefit of the CMS collaboration.