This study was carried out at the Animal Farm, Faculty of Veterinary Medicine in Ismailia and was aimed to investigate any association between oxidative status and placental retention in buffaloes. The materials involved collection of blood and placental tissue (cotyledons) samples from 15 multiparous buffalo-cows with retained placenta matched with 15 cases of the same parity with normal placental drop as controls. Placental samples were homogenized and the levels of lipid peroxidation products as well as the activity of glutathione were determined. Blood samples were immediately centrifuged and the concentrations of oestradiol-17B, progesterone, cortisol and total antioxidant capacity (TAC) were measured. The results revealed that oxidative stress could be a mediator for retained placenta in buffaloes. High significant (P<0.01) levels of lipid peroxidation products and glutathione activity were recorded in the retained placental tissues compared to that of not retained cotyledons. Serum total antioxidant capacity and cortisol showed high significant (P<0.01) values in buffaloes with retained placenta compared with those of the controls. A high significant (P<0.01) decrease in the serum levels of oestradiol-17B was found in the diseased group compared with the control group.