We study the electronic and magnetic properties of the Cr2MnSb full-Heusler alloy using ab initio electronic structure calculations. We take into account both possible L2(1) structures (CuHg2Ti and AlCu2Mn types) and we determine the phase diagram. Both types of the L2(1) structure present similar magnetic properties and they are ferrimagnets. Moreover they also present the half-metallic property for a wide range of lattice constants resulting to a half-metallic antiferromagnet. Thus Cr2MnSb is a promising material for future spintronic applications. (C) 2009 Elsevier B.V. All rights reserved.