Link slabs, which are often made of concrete and reinforcement and used as connecting elements between bridge decks in pre-cast beam bridges, show complicated load bearing behaviour. Under repeated loading, especially through traffic, link slabs may fail in fatigue during the service life with high probability. Therefore, a numerical study of fatigue of link slabs was performed in this thesis,. To determine the stiffness and stress of link slabs a new computational model for reinforced concrete elements under repeated loading was developed. The new model was implemented in a self-developed computational program BMAP. Using the new calculation model many numerical studies of behaviour of link slabs were conducted, in which the stress and strain states of structural elements were determined in dependence of any number of load cycles and under different boundary conditions. The main influence parameters of cross sectional load bearing were also examined. Based on these results it could be found that the stiffness of link slabs has a large effect on their fatigue behaviour under traffic load. This was investigated in two major link slab types. The results show that the fatigue load by the link slab in bridges, which has a large gap between two adjacent beam ends, is significant large. Since the length of the link slab in this case is limited by the dimensions of piers and the very high required reinforcement ratio, the use of this link slab type should be avoided in practice. A newly developed link slab type with regard to a better load capacity especially to fatigue is presented. It could be shown that the new link slab type with the optimized dimensions has an increased potential for applications in practice. The thesis is rounded off with the development of a new fatigue design concept for link slabs. This design concept provides an easy, but also accurate way of forces calculation, fatigue analysis and lifetime prediction of any link slab.