Shot peening, apart from its various projected effects, modifies also the surface state of treated components in terms of surface irregularities. Bearing in mind that both the macroscopic and the microstructure surface characteristics strongly affect the mechanical structures' functionality, it is essential to carefully study the surface state of treated components. To assess the surface roughness evolution induced by shot peening, a 3D finite element model of the process is used to investigate surface topography alterations as a function of peening parameters and processing time. Discrete data obtained from the numerical simulations are subsequently elaborated to calculate the conventional roughness parameters. The results obtained from the numerical simulations, correspond quite well with the roughness values measured experimentally on shot peened specimens. It is indicated that the developed numerical model provides an efficient estimation of surface characteristics of shot peened specimens, in terms of surface roughness parameters and thus can be used to properly select the peening parameters considering the eventual surface roughness. (C) 2012 Elsevier B. V. All rights reserved.