Alzheimer’s disease (AD) is a neurodegenerative disorder that impairs mental development ability and interrupts neurocognitive function. The ketogenic diet (KD) is a low-carbohydrate with high-fat and adequate-protein. The present study was conducted to investigate the effect of KD on Aluminum chloride (AlCl3) - induced Alzheimer’s disease in rats. Forty male albino rats were split into four groups: group 1 and group 2 were kept as negative and positive control rats (AlCl3-treated rats), respectively, and were feeding on the normal basal diet. While the other remaining two groups treated with AlCl3 were fed on ketogenic diets (62% fat, 14% protein and 14% carbohydrate) and (67% fat, 14% protein and 10% carbohydrate), respectively, for 8 weeks