The electronic structure and structural properties of LaSb and LaBi are studied by means of the self-consistent tight binding linear muffin tin orbital method. The relative stabilities of LaSb and LaBi at high pressures in the Rock salt, Primitive tetragonal and CsCl structures are analysed. At compressed volumes, these compounds are found to favour the tetragonal phase rather the CsCl phase, which can be seen from the total energy curves. The transition from B1 to PT occurs around 8.6 and 11.2 GPa in LaSb and LaBi, respectively. The ground state properties of these compounds such as equilibrium lattice constant, bulk modulus are calculated and are in good agreement with the experimental results. The band structure and density of states are plotted for B1 and tetragonal phase and are compared with the available literature. © 2002 Elsevier Science B.V. All rights reserved.