We present the results of the combination of searches for the standard model Higgs boson produced in association with a W or Z boson and decaying into b bbar using the data sample collected with the D0 detector in p pbar collisions at sqrt{s}=1.96 TeV at the Fermilab Tevatron Collider. We derive 95% CL upper limits on the Higgs boson cross section relative to the standard model prediction in the mass range 100 GeV