The aim of this PhD thesis is an improved methodology for the computation of fatigue safety factors for aluminium high-pressure die casted (hpdc) components. Conventional computations tend to underestimate the potential of components by a factor of 2. Till now the inhomogeneous pore distribution could not be considered in the computation of the fatigue safety factor due to the lack of appropriate models. Two areas have to be considered for a realistic computation of the fatigue safety factor the inhomogeneous pore distribution in the component and the influence of the pores on the fatigue strength. A systematic testing of the relevant influences on the fatigue strength of an aluminium high-pressure die casting alloy was performed. A fracture mechanics model was derived based on the results of the comprehensive testing program. This allows computing the fatigue strength depending on the pore size. The second part of this thesis deals with the characterization of the inhomogeneous pore distribution. An empirical model the so called statistical porosity model has been derived. This model allows an estimation of the pore distribution throughout a component using the results of the casting simulation together with the process parameters. Through the combination of the two models the fracture mechanical material model and the statistical porosity model it is possible to consider the influence of an inhomogeneous pore distribution on the fatigue safety factor.