After 14-day space flight of rats onboard Cosmos 2044 in their blood plasma, homogenates of liver, skeletal muscles and myocardium there were determined the parameters of peroxide oxidation of lipids (POL) and system of antioxidant defense: content of dienic conjugates (DC), malonic dialdehyde (MDA), schiff bases (SB), tocopherol (TF), total antioxidative activity (AOA, only in plasma), activity of antioxidative enzymes (only in tissues) superoxide (SOD), catalase, glutathione-peroxidase (GP), glutathione-reductase (GR). In the animal liver there was a decrease in SB content and an increase of SOD, catalase and GP activities. Skeletal muscles exhibited a reduced SB concentration. In myocardium there was a reduction of DC and SB levels, activity of GR with an increase of TF concentration, activity of SOD and catalase. In the blood plasma there occurred a decline of SB and TF contents and an elevation of MDA and total AOA concentrations. The authors drew a conclusion about a compensated process of POL in the tested animals and about the relation of the observed changes with body response to the final phase of the space mission and acute gravitational stress during a readaptation to the Earth environments. On the basis of the analysis of similar data from shorter-duration space experiments, the noted changes in the parameters of the system of POL and antioxidant defense are considered a universal response which does not directly depend on duration of the orbital phase of a space mission.