The self-consistent electronic structures and total energies for the crystalline α-SiO2 and β-Si3N4 are studied by means of the first-principles orthogonalized linear combination of atomic orbitals method. The calculated band structures are compared with the earlier non-self consistent results. The total energies in the local density approximation are evaluated as a function of lattice parameters. Reasonable values of equilibrium lattice constants and cohesive energies are obtained but the bulk modulus for α-SiO2 is overestimated.