[en] DO/ has measured the inclusive production cross section of W and Z bosons in a sample of 13 pb^-1 of data collected at the Fermilab Tevatron. The cross sections, multiplied by their leptonic branching fractions, for production in p bar p collisions at √ (s) =1.8 TeV are σ_W B(W→e ν)=2.36 ± 0.02 ± 0.08 ± 0.13nb, σ _W B(W→μν)=2.09 ± 0.06 ± 0.22 ± 0.11nb, σ _Z B(Z→e ⁺ e ^-)=0.218± 0.008 ± 0.008 ± 0.012nb, and σ _Z B(Z→μ ⁺ μ ^-)=0.178 ± 0.022 ± 0.021± 0.009nb, where the first uncertainty is statistical and the second systematic; the third reflects the uncertainty in the integrated luminosity. For the combined electron and muon analyses, we find σ _W B(W→ l ν)/σ _Z B(Z→l ⁺l ^-)=10.90 ± 0.52. Assuming standard model couplings, we use this result to determine the width of the W boson, and obtain Γ (W)=2.044 ± 0.097 GeV. copyright 1999 The American Physical Society