We present the results of ab initio Hartree-Fock calculations of the LaMnO3 (0 0 1) and (1 1 0) polar surfaces. Using 7- and 8-plane slabs periodic in 2D along the x, y-axes, we compare the properties of a stoichiometric slabs with structural oxygen vacancies, and non-stoichiometric, defect-free slabs, analyze the dispersion of the effective charges near the surface, and calculate the surface energy, for both ferromagnetic and antiferromagnetic spin orderings in a slab. (C) 2004 Published by Elsevier B.V.