Immobilization stress induces the formation of reactive oxygen species and leads to the oxidative stress injury in various tissues. The present study was carried out in order to assess the effect of immobilization stress on the level of lipid peroxides and activities of antioxidant enzymes, and the protective role of the antioxidant vitamins E (α-tocopherol) and C (ascorbic acid) against the reactive oxygen species (ROS) produced by immobilization stress. Forty adult male albino rats were used in the present study; Animals were divided into four groups (10 rats each); (1)control group (2)stressed group (subjected to immobilization for 4 hours) (3)stressed group, treated by α-tocopherol, 10mg/kg, p.o daily for 2 weeks (4)Stressed group, treated by ascorbic acid, 80mg/kg, p.o daily for 2 weeks. Levels of thiobarbituric acid reactive substances (TBARS) level and activities of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSHPX) in liver and heart were determined. In this study a significant dramatic increase in liver and heart TBARS level in immobilized group has been recorded; this may indicate the generation of ROS as a result of immobilization stress. A significant decrease in the activity of liver and heart SOD and GSHPX have been observed. The endogenous antioxidant mechanisms were fortified by administration of the free radical scavengers, vitamin C and E. A significant reduction in liver and heart TBARS level was recorded. Moreover, the antioxidant enzymes significantly restored their activities by administering the antioxidant vitamins, E and C, It is concluded that immobilization stress induces lipid peroxidation and altrers the antioxidant enzyme activities; the protective role of vitamins C and E may be due to stimulation of the antioxidant enzyme synthesis or reduction of their consumption.