Stress has undoubtedly become an integral part of human life. Elevated levels of malondialdehyde (MDA) one of the by-products of lipid peroxidation has been reported in various diseases1. The amygdala has attracted continued interest because of its central role in processing emotional information. The idea that the brain categorizes stressors and uses response pathways that vary according to the category has gained significant support. The present study was designed to elucidate the possible role of amygdala nucleus on chronic physical and chronic psychological stress induced tissue MDA level. All procedures were performed as per the guidelines established by the Institutional Animal Ethics Committee. Adult Wistar albino rats were divided into three major groups normal (N), sham lesioned (SL) and amygdala lesioned (AL). Each major group was further subdivided into control group (C) and two stress groups. Every group contained ten animals .Rats were anesthetized by using Pentobarbitone sodium (40 mg/kg, intraperitonially) .The amygdala lesion was performed according to the stereotaxic coordinates as prescribed in the Paxinos and Watson rat2. The stressed group of rats were subjected to chronic swimming (physical) and chronic immobilization (psychological) stress for 60 days. Tissue MDA levels (nanomoles of MDA/g wet tissue) was estimated by Kartha and Krishnamurthy method3. The datas were summarized using mean ± SEM .For normally distributed data one way ANOVA was used. The data of pre and post lesion was analyzed using two ways ANOVA . P<0.05 were considered as statistically significant. Exposure to chronic swimming stress significantly (P<0.001) increased the tissue MDA level [Swimmingstress:(Heart,Liver,Kidney);N(20.22±0.86,39.26±0.20,20.12±0.88)SL:(21.438± ±1.61,41.425±0.703,21.291±0.633)AL:(19.70±2.27,41.425±0.703,21.291±0.633).Immobilizationstress:(Heart,Liver,Kidney);N:18.80±0.22,40.22±1.20,22.91±0.54)SL:(18.865±0.49,40.789±1.30,21.21±0.95):(23.620±0.487,59.290±0.98,30.010±0.56)]. However, the stress induced increase in MDA level in amygdala lesioned rats was significantly more (P<0.001) during immobilization stress [(Heart, Liver, Kidney; 23.620±0.487, 59.290±0.98, 30.010±0.56)] than swimming stress [Heart, Liver, Kidney; 19.70±2.27. 41.425±0.703, 21.291±0.633]. The present result shows that amygdala nucleus plays a potent role in minimizing the stress induced MDA formation during the exposure to psychological type of stress rather than a physical type of stress like swimming. In this direction, the present study provides the supportive evidence that the response of a psychological stressor to a larger extent is regulated by the amygdala.Key words: Amygdala, Immobilization, Swimming, Lesion, MDA