A new model was presented for describing the adsorption-induced surface reconstruction process. Different situations could be observed; depending upon the characteristics of the metal–metal, adsorbate–adsorbate and metal–adsorbate interactions. Neglecting the adsorbate–adsorbate interactions, an analytical treatment was used which led to exact solutions for the free energy of the system in each case. The ground state was calculate and, by means of Monte Carlo simulations and finite-size scaling theory, the critical temperature was evaluated as a function of coverage. The phase diagrams of the model were analysed and compared with experimental findings. A New Lattice-Gas Model for Describing the Adsorption-Induced Surface Reconstruction Process. A.A.Tarasenko, F.Nieto, V.Pereyra, C.Uebing: Surface Science, 1999, 441[2-3], 329-43