We investigated the acute effect of single-dose cadmium (Cd) treatment on lipid peroxidation and antioxidant enzymes in liver and kidney of rats following an ovariectomy operation. Twenty-eight female Wistar albino rats were used and were divided into four groups: I, control (n=7); II, cadmium (Cd, n=7); III, ovariectomized (Ovx, n=7); and IV, ovariectomized+cadmium (Ovx-Cd, n=7). Fourteen of the rats were ovariectomized. Twelve weeks later, cadmium chloride (CdCl(2), 5 mg/kg) was administered i.p. as a single dose to the Cd and Ovx-Cd groups. Twenty-four hours after the injection, all rats were sacrificed and had their liver and kidney tissues removed for the measurement of superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) levels. SOD activity showed a significant decrease (P<0.001) in both organs of Ovx and Cd rats in comparison to controls. CAT activity was significantly decreased (P<0.01) in the liver of Ovx and Cd groups but not in the kidneys of both groups compared to control values. MDA concentrations were higher (P<0.05) in both organs of Ovx and Cd rats than those values observed in the control group. Similar patterns of changes were observed in the Ovx-Cd rats, but the increase in the MDA levels and the decrease in the antioxidant enzymes for the Ovx-Cd group were higher than those of the Ovx and Cd groups. Based on the data, it can be stated that cadmium increases the effect of ovariectomy on lipid peroxidation, impairs the antioxidant defense system, and induces oxidative stress.