The results of a search for pair production of a heavy, top-like quark, t', in the decay mode t'(t) over bar' -> bW(+)(b) over barW(-) -> bl(+)v (b) over barl(-) (v) over bar are presented. The search is performed with a data sample corresponding to an integrated luminosity of 5.0 fb(-1) in pp collisions at a center-of-mass energy of 7 TeV, collected by the CMS experiment at the LHC. The observed number of events agrees with the expectation from standard model processes, and no evidence of t'(t) over bar' production is found. Upper limits on the production cross section as a function of t' mass are presented, and t' masses below 557 GeV/c(2) are excluded at the 95% confidence level. (C) 2012 CERN. Published by Elsevier B.V. All rights reserved.