Magnesium oxide (MgO) nanoparticles were synthesized and assayed for antiplasmodial activity in vivo. MgO nanoparticles were synthesized using sol-gel process and characterized using SEM, FTIR AND UV-VIS spectral study to confirm the formation and size of the nanoparticles. 20% of LD50 value was used to formulate a graded dose of 300, 200 and 100mg/kg. Then 30 mice were group into 5 containing six mice each and were inoculated with 0.2ml of ANKA strain of plasmodium berghei intraperitoneally and were left for the next 7 days before treatment with the graded doses based on their body weight.20/120mg/kg standard dose of Artemether lumefantrine was use as positive control while negative control were given no treatment at all. Data were analyses using mean percentage parasite clearance rate, analysis of variance (ANOVA) and Tukey honestly significant difference test. MgO nanoparticles showed a remarkable clearance rate of 98.8% just after 24hours of administration and at the end of the four day curative model all the parasites were cleared from the blood. There was statistically significant difference between groups as determine by one- way ANOVA F (3,16) =24.30,p=3.36E-06. This clearly showed that MgO nanoparticles are superior in the clearance of the ANKA strain of plasmodium berghei in infected mice.