The Main Injector era of the Fermilab Tevatron is about to begin. Its first collider physics run (Run II) will start in the spring of 2001, with p p collisions at √ s = 2.0 TeV and a expected integrated luminosity of 2 fb −1 delivered in the first two years. The DØ detector is undergoing an extensive upgrade in order to take full advantage of this high luminosity running. The upgraded detector's silicon vertex detector, inner tracker, and muon trigger arrays, will make a rich B physics program possible at DØ. In this paper we discuss our prospects for key measurements which include CP violation in B → J/Ψ + K s decays, CP asymmetries in two body hadronic B decays, B s mixing, as well as spectroscopy and lifetime measurements of beauty baryons such as the Λ b .