  We present a next-to-leading-order calculation of the production of a Z boson
with two jets, one or more of which contains a heavy quark (Q=c,b). We show
that the cross section with only one heavy-quark jet is larger than that with
two heavy-quark jets at both the Fermilab Tevatron and the CERN LHC. These
processes are the dominant irreducible backgrounds to a Higgs boson produced in
association with a Z boson, followed by h->bb. Our calculation makes use of a
heavy-quark distribution function, which resums collinear logarithms and makes
the next-to-leading-order calculation tractable.
