The corrosion behaviour of Al-alloy/Seashell (SeSh) composites in the acidic and alkaline environment was investigated in this study. Fifteen Aluminum alloy composites samples were produced using stir casting technology by varying the amount of reinforcement (1.5, 3.0, 4.5, 6.0, 7.5 wt%) and particle size (100, 150, 200 µm) of milled SeSh in the Aluminium alloy matrix. The corrosion rate was determined using a weight loss technique after 18 days of immersion at an interval of 72 hours. It was observed that 6.0 wt% of the 100 µm reinforced Aluminium alloy had the best corrosion resistance in acidic and alkaline environments. In general, the reinforced Al-alloy had better corrosion resistance when compared with the unreinforced samples. Analyses of the results show that aluminum alloy seashell composites exhibited better resistance to corrosion in the alkaline environment than the acidic environment.