The aim of this study was to examine changes in tissue Cu/Zn- and Mn-SOD contents and gene expression following mild and severe burns in a rodent burn model. [Experimental design] Eighteen male Wistar rats, weighing 208-278 g, were divided into a sham-burn group (Group S) and two burn groups, one (Group A) receiving burns to 35% of the body surface and the other (Group B), to 60% (mortality 70%). The animals were not given fluid resuscitation; they were sacrificed at 3-hours postburn, and blood, lungs and kidneys were collected for biological analysis. Cu/Zn- and Mn-SOD contents of tissues and plasma were measured using ELISA. The mRNA expressions of Cu/Zn- and Mn-SOD were shown by Northern blot analysis. [Results] The mRNA expressions of tissue (lung and kidney) Mn-SOD were significantly higher in Group B than in the other groups, as was the mRNA expression of lung Cu/Zn-SOD. Nevertheless, tissue SOD contents in Group B were significantly lower than those in Group A. [Conclusion] Tissue SOD synthesis might be inhibited in lethal burns in spite of strong mRNA expression of SOD.