Parton distributions and the LHC: W and Z production

W and Z bosons will be produced copiously at the LHC proton-proton collider . We study the parton distribution dependence of the total production cross sections and rapidity distributions, paying particular attention to the un certainties arising from uncertainties in the parton distributions themselv es. Variations ill the gluon, the strong coupling, the sea quarks and the o verall normalisation are shown to lead to small but non-negligible variatio ns in the cross section predictions. Ultimately, therefore, the measurement of these cross sections will provide a powerful cross check on our knowled ge of parton distributions and their evolution.