  We present a study of l\nu b\bar{b} and l+ l- b\bar{b} production at hadron
colliders. Our results, accurate to the next-to-leading order in QCD, are based
on automatic matrix-element calculations performed by MadLoop and MadFKS, and
are given at both the parton level, and after the matching with the Herwig
event generator, achieved with aMC@NLO. We retain the complete dependence on
the bottom-quark mass, and include exactly all spin correlations of final-state
leptons. We discuss the cases of several observables at the LHC which highlight
the importance of accurate simulations.
