Additive manufacturing (AM) processes, such as powder-based or sintering methods, offer a high degree of flexibility to produce parts with complex geometries, even for structural applications that typically require a high strength of the components. However, the poor surface quality of as-built parts results in a low fatigue strength compared to conventionally manufactured components. Thus, the use cases for metallic AM components in safety relevant applications such as aviation and transport are currently limited. Reasons for the poor fatigue strength are the high surface roughness and defects such as pores and lack-of-fusion (LOF) near the surface layer. These notch-like features act as crack initiators. To improve the fatigue strength of the surface layer, mechanical surface treatment (MST) methods offer great potential, e.g. shot peening or deep rolling are widely used for post-treatment of conventionally manufactured components. However, relatively few studies exist for AM materials. In the ongoing IGF project 22833N “AM Oberfläche”, MST methods such as shot peening and deep rolling are investigated to improve the properties of additively manufactured AlSi10Mg and 316L parts. In addition to experimental investigations to characterize the surface layer and the fatigue strength of different material states, the MST process is modelled via finite-element-based process simulation. A strain-rate dependent cyclic plasticity model with kinematic hardening is applied to account for the material behavior during the shot peening and deep rolling processes. As a perspective within the project, the developed methodology will also be applied to demonstrator components, considering the MST in a dimensioning scheme similar to the FKM guidelines widely used in the industry.