Two experiments were conducted to evaluate the nutritive values of defatted rice bran (DRB) and examine the effects of its dietary supplementation on broiler performances. In Experiment Ⅰ, to measure true metabolizable energy (TME), nitrogen corrected true metabolizable energy (TMEn), and true amino acid availability (TAAA), 30g of DRB sample was forced-fed to each of 16 ISA-Brown roosters followed by a 48h collection of excreta. The TME and TMEn values for DRB were 2.19 ㎉／g and 2.05 ㎉／g, respectively. The mean value of TAAA of the 15 amino acids in DRB was 77.29％. In Experiment 2, a total of 72 Avian broiler chicks were divided into 4 groups with 3 replicates of 6 birds per replicate, and fed one of the experimental diets containing 0, 5, 10 or 15％ of DRB. Feed intake, weight gain, feed conversion rate, and body composition were measured for 3 weeks. Although there were no significant differences (P≥0.05), body weight gain and feed intake of chickens fed a diet containing 15％ DRB were slightly higher than those of the other groups. From these results, it can be concluded that feed formulation using TMEn and TAAA of DRB is an effective method for assuring feed quality and DRB can be supplemented to broiler rations up to 15％ level.