The potential of friction stir welding (FSW) tor dissimilar joining has been evaluated. Different joint configurations and welding speeds were used to study the effect of welding parameters on weld quality and properties. High quality dissimilar friction stir welds were produced between AA 5083 and AA 6082 aluminium, with mechanical properties approaching those of welds in AA 6082. Al-clad thin sheet AA 2024 was successfully welded, illustrating the potential of using FSW for joining clad material. Also Cu and AA 5083 was joined with promising results. A higher welding travel speed generally resulted in higher strength and better ductility. The nugget annual ring pattern was pronounced in AA 5083/ AA 6082 welds, consisting of intimately bonded alternating regions with compositions corresponding to the two alloys. Possibilities of optimising productivity and weld properties are discussed in terms of the relation between microstructure, properties and welding conditions.