Lightweight alloys have been extensively used in the aeronautic industry for a long time and nowadays their application in the automotive industry has been increasing remarkably as well. The reasons for this are associated to fuel consumption reduction and also attendance to new government rules issues. As a consequence lightweight components may need to be connected to other parts of a bigger structure during the production cycle of mechanical parts. Resistance spot welding (RSW), riveting and self piercing riveting are the most common techniques used for spot connections in mechanical parts. However some lightweight alloys are difficult to weld using RSW and are likely to result in poor weld quality. Also high energy consumption and high investing costs are other problems associated to these conventional techniques. Recently a solid-state joining process called friction spot welding (FSpW) was developed and patented by GKSS Research Centre (Germany) in which a special tool comprised of three independently moving parts: pin, shoulder and clamping ring is used. The process is based on the well known FSW process and the bonding is formed by means of stirring the material at the interface of overlapping sheets. In this work the friction spot joining of aeronautic AA2024-T3 claded and AA7075-T6 alloys was studied aiming the investigation of the effect the process parameters have on the mechanical and metallurgical properties of the joint. The joints resistance was assessed by means of shear tensile and cross tensile tests. OM and SEM were used for evaluation of welding zones, defects and fracture behavior of the joints. The results obtained showed that good quality, strong and reproducible joints are possible by FSpW. However some process parameters are likely to result in weld defects and the proper set of parameters used for a determined alloy should take this factor into account.