Close-coupling calculations of positron scattering from atomic sodium are performed from threshold to 100 eV. The alkali atom is represented by a frozen-core model based upon the Hartree - Fock approximation. The close-coupling calculations are performed in a model containing multiple sodium (3s, 3p, 4s, 3d, 4p) and positronium states (1s, 2s, 2p, 3s, 3p, 3d). Subsidiary calculations with three and ten positronium states were performed at selected energies to test the convergence of the positronium formation cross section. The predicted total cross sections agree with the experimental data of Kwan et al but there are differences with the data of Kauppila et al. The net positronium formation cross section underestimates the experimental data of Zhou et al.