The experiment was conducted to compare the effect of different selenium sourceson the expression of glutathione peroxidase 1(GPx1) and iodothyronine deiodinase 1(Dio 1) mRNAin mice by quantitative real time PCR. A total of sixty male Kunming mice at average body weightof 20g were allotted to three groups in a randomized Complete block design,including twotreatments and one Control. Mice in Group 1 were fed a basal diet as Control,while mice in Groups2 and 3 were fed the basal diet supplemented with 0.1 mg/kg selenium as sodium selenite orselenized yeast,respectively. Whole feeding experiment lasted for 30 d. At the end of the feedingtrial,liver mRNA levels of GPxl and Diol were determined by quantitative real time PCR,as wellas growth performance,body Composition,blood and GPx activity were determined. The resultsshowed that no significant differences in overall growth performance and body Composition,including body weight,body length,heart weight,kidney weight and liver weight,were foundbetween the experimental groups(P > 0.05). Blood GPx activity increased in all of the seleniumsupplemented groups Compared with Control group(P < 0.01). However,blood GPx activity inselenized yeast group was higher than that in sodium selenite group(P < 0.05). Liver mRNA levelsof GPxl and Diol also increased in the two selenium supplemented groups Compared with thecontrol group(P < 0.05),while there was no significant difference between the sodium selenite andselenized yeast groups(P > 0.05). In Conclusion,selenium increased the mRNA expression of Gpxland Diol genes in murine liver,and there was no significant difference between the organic orinorganic form of selenium used.