The authors compute the next-to-next-to-leading order (NNLO) QCD corrections to the production of a W-boson in association with a bottom- quark pair at hadron colliders. This calculation is the very first → process with a massive external particle to be studied at such a perturbative order. The authors present numerical results for the cross section and differential distributions for this process at the LHC with 8 TeV center-of-mass energy.