The paper describes a method for including topographic effects in a thermo-visco-elastic model. An approximate methodology for the consideration of topography in the computation of thermo-viscoelastic displacement and gravity changes was used. It gave us a relatively general and simple solution useful for solving the inverse problem. Our results show that for volcanic areas with an important relief, the perturbation of the thermo-viscoelastic solution (deformation and total gravity anomaly) due to topography can be quite significant. In consequence, neglect of topographic effects can give a rise to significant errors in the estimation of surface displacements and gravity changes, and therefore in the estimation of the intrusion characteristics obtained solving the inverse problem.