The La doped Cr-based double perovskite Ba2-xLaxCrMO6, where M = Mo, Nb and (x = 0, 1 and 2), have been studied by employing full potential linear muffin-tin orbital (FP-LMTO) within the atomic plane wave (PLW) method. Effects of La-doping on structural, electronic and magnetic properties of Ba2-xLaxCrMO6 have been studied within the correlated local-spin-density approximation (LSDA + U) method. The crystal structure of Ba2-xLaxCrMO6 decreases from cubic Fm-3m (x = 0, 1) to tetragonal 14/m (x = 2). The La-doping favors the reduction of Cr3+ and M5+ which plays a vital role in determining the electronic and magnetic properties. The results show that all Ba2-xLaxCrMO6 compounds are halfmetallic-ferrimagnetic, except Ba2CrNbO6 (x = 0), which is a ferromagnetic-insulator. With increasing x content the magnetic moment of Mo and Nb distinctly increases and the doped electrons occupy chiefly the 4d down arrow orbitals. (C) 2014 Elsevier B.V. All rights reserved.