Lipid peroxidation (LPO) is one of the main events induced by oxidative stress. The aim of our study was to investigate the influence of 30 min cold-immobilization (model of acute stress used in this experiment) on LPO in the brain, heart, liver and stomach homogenates of the rats. LPO was determined by measuring of the contents of thiobarbituric acid reactive substances (TBARS), conjugated dienes (CD) and sulfhydryl groups (SH). Experimental stress induced enhancement of TBARS formation in the liver and increased level of the CD in the heart, stomach and liver, while in the brain both parameters were found to be decreased. The levels of TBARS were not changed in the heart and in the stomach, too. The concentrations of SH-groups were decreased in the heart, brain and stomach, while in the liver the parameter was found to be not changed. The results of this study showed the increase of LPO in the heart, stomach and liver under stress conditions. It could be supposed that LPO may be involved in mechanisms of stress injury in different tissues.