This study was conducted to determine the efficacy of nano-composite Magnesium oxide and Silver oxide (MgO-SiO2) to reduce the toxic effects of Aflatoxin B1 (AFB1) in adult male rats for 8 weeks. Animals were randomly divided into a control and three experimental groups (25 each). The first experimental group received feed contained 200 ppb (0.2 mg/kg) AFB1. The second group received feed contained 200 ppb AFB1/kg and 0.5g/kg nano-composite (MgO-SiO2). Rats of the third experimental group received 0.5g/kg nano-composite (MgO-SiO2). Results showed that AFB1 markedly reduced body weight gain and food and water consumption. Postmortem examination revealed that  AFB1 intake also induced pathologic changes in the liver and spleen. Activity of lymphocytes transformation and serum lysozymes activity showed significant changes. On the other hand, the deleterious effects of AFB1 were alleviated in the group received 200 ppb AFB and 0.5g/kg nano-composite (MgO-SiO2). These findings suggested that MeO-SiO has high affinity to adsorb AFB1 and can effectively modulate its toxicity in rats and may offer a novel approach t the preventive management of aflatoxicosis in animals.