We present a search for Wb production in p collisions at =1.96 TeV in events containing one electron, an imbalance in transverse momentum, and two b-tagged jets. Using 174 pb-1 of integrated luminosity accumulated by the D0 experiment at the Fermilab Tevatron collider, and the standard-model description of such events, we set a 95% C.L. upper limit on Wb production of 6.6 pb for b quarks with transverse momenta p>20 GeV and b separation in pseudorapidity-azimuth space bb>0.75. Restricting the search to optimized b mass intervals provides upper limits on WH production of 9.0–12.2 pb for Higgs-boson masses of 105–135 GeV.