The linear combinations of Gaussian-type orbitals-fitting function (LCGTO–FF) technique, as embodied in the program package FILMS, has been extended to include spin-polarization effects. The spin-polarized LCGTO–FF method is described here. Test results are presented for square monolayers of seven 3d-transition metals (Ti, V, Cr, Mn, Fe, Co, and Ni) at the lattice constant of Ag(001). The LCGTO–FF results compare favorably with previous results obtained with the FLAPW technique. © 1993 John Wiley & Sons, Inc.