Nowadays, soft tissue expanders are being increasingly, used to create local skin flaps which can cover relatively large tissue defects. This involves inserting a silicon-rubber balloon (prosthesis) in its collapsed state under the subcutaneous tissue of the patient, closing the incision, and then inflating the balloon slowly with a saline fluid through a one way valve. The valve is part of the balloon prosthesis. Obviously, the skin expands in the form of a dome in unison with the balloon underneath it. In preliminary studies designed to evaluate the behavior of skin created by soft tissue expansion, the viscoelastic proprieties of skin were ignored. The objective of the present work is model skin as an isotropic homogeneous viscoelastic material using the finite element method for large deformation in axisymmetric expanders. In finite element analysis we are using a linear viscoelastic model with three different kinds of elements, solid, shell and membrane, looking for the best element to describe the model. We are also making a parametric study, varying the thickness of the elements and comparing the results. To develop this finite element analysis, we are using the ABAQUS program . The methods have been validated using results from previous experimental works . In the future, we intend to model non-axisymmetric expanders and apply this work to in-vivo experiments.