The seam quality as well as the static and cyclical strength of welded joints made of Al die-cast or mixed joints made of AL die-cast with Al wrought alloys depend directly on the casting quality and the welding process used. Generally applicable design parameters are not yet available for such welded joints, especially not under consideration of the real weld quality. The aim of the research project applied for is the statistically verified determination of the static and cyclical strength of welded Al-pressure die-cast joints or mixed joints of Al-pressure die-cast and wrought Al-alloys, taking into account the unavoidable weld seam irregularities. In this context, both the commonly used welding processes MIG (reference) and conventional laser beam welding as well as new process developments for reducing the seam porosity, such as electron beam multi-bath welding and laser beam welding with high-frequency beam oscillation, are considered. The investigations are carried out on the butt joint, lap joint and offset butt joint types typical of practice. The investigations are based on the statistically evaluated characterization of the external and internal weld seam irregularities by optical 3D measurements or metallography and CT analyses. Subsequently, the samples are subjected to quasi-static and cyclical transverse tensile tests and Wöhler lines are generated. Finally, the determined strength parameters are evaluated taking into account the recorded quality characteristics. In conjunction with this, the calculated fatigue strength is checked and, if necessary, modified according to the notch stress concept for the considered welding processes and seam qualities in accordance with the regulations. Finally, generally valid recommendations for the mathematical evaluation of arc and beam welded Al die-cast and wrought Al alloys are derived.