We present the results of asearch for W′ boson decaying to electron-neutrinopairs in pp collisionsat a center-of-mass energy of 1.96 TeV, using a data sample corresponding to 205  pb−1 of integrated luminosity collected by the CDFII detector at Fermilab. We observe no evidence for this decay mode and set limits on the production cross section times branching fraction, assumingthe neutrinos from W′ boson decays to be light. Ifwe assume the manifest left-right symmetric model, we exclude a W′ boson with mass less than 788  GeV/c2at the 95% confidence level.