The authors introduce the multi-scale modelling approach of service properties and recent results that best reflect the complex behaviour of industrial materials. They describe the main modelling tools and highlight the essence of experimental checking at the appropriate scale. The authors describe in details the progress that has been accomplished in the prediction of the energy of atom-scale defects in steels, as essential input data to model the kinetics of microstructure evolutions under radiation. The authors present the multi-scale prediction of mechanical properties along with the particular issue of the nuclear fuel.