The endothelial permeability of aorta (EPA) is influenced by atherosclerosis. Whether the physiological difference in EPA is a sex-dependent phenomenon remains to be determined. The objective of this study was to determine the EPA difference between male and female rabbits. An experimental model was designed to obtain 4 groups of animals. The ovariectomized rabbits were fed with normal (group I) and 1% cholesterol-rich diets (group III). The male rabbits also received normal (group II) and cholesterol-rich diets (group IV). After 5 wks, the EPA was measured by Evan Blue (EB) dye uptake method. The EB uptake was significantly (p<0.05) lower in females, regardless of the diet they used. In groups I to IV, the mean±SD EB uptake was 4.83±2.06, 15.15±2.91, 7.01±2.40, and 20.58±3.62 mg/g weight of aorta, respectively. The lower EPA in females may play a role in reducing the risk of development of atherosclerosis.