In-situ fabrication of metal matrix nano composites has various advantages such as the formation of clean particle-metal interface with strong bonding. In this study, three types of metal oxides powders (commercial TiO2, commercial ZnO, and recycled Pyrex) were used to inject into the pure aluminium melt to fabricate in-situ aluminium matrix nano composites via liquid-state stir casting at 850 °C followed by a hot rolling process. SEM and FESEM microstructural characterizations, as well as EDAX analysis, were used to show if in-situ reactions occurred between molten aluminium and metal oxides to form nano alumina particles as the reinforcement. Tensile and microhardness tests were also applied on the rolled nano composites to identify the effect of metal oxide type and amount on the mechanical properties. It was found that using recycled Pyrex crushed powders led to the formation of a uniform distribution of alumina nanoparticles, while fine-micron ZnO and especially TiO2 powders could not be uniformly distributed into the melt for complete reaction occurrence.