This work studied the effect of malaria infection and antimalarial drugs on oxidative stress in 259 pregnant and nonpregnant women at Ade-Oyo hospital, Ibadan, Nigeria. Oxidative stress was determined by measuring serum lipid peroxidation, ascorbic acid, and reduced glutathione (GSH) levels using spectrophotometer. The results showed that mean lipid peroxidation was significantly higher (p < 0.05) in malaria positive than malaria negative women, while GSH and ascorbic acid levels were significantly (p < 0.05) reduced. The parasite density was significantly reduced in patients who had taken antimalarial drugs relative to those without. While mean ascorbic acid and GSH levels were significantly reduced in those who had taken drugs as compared with those without drugs, the lipid peroxidation level was significantly higher in them. The increase in lipid peroxidation and decrease in GSH and ascorbic acid levels in women who were malaria positive and in those who had taken drugs is indicative of oxidative stress.