This study was carried out to investigate the supplementary effects of ${gamma}$-oryzanol on the blood glucose level in diabetic mice. We supplied 2 experimental diets (CO without and GO with 0.2% ${gamma}$-oryzanol) to diabetic mice for 8 weeks. Diet intake, body weight and levels of blood glucose, hemoglobin $A_{lc}$ and insulin were measured. Though there was no significant difference in diet intake between experimental groups, the concentration of fasting blood glucose and blood glucose area from glucose tolerance test in diabetic mice was lower in GO group than CO group during the supplementary period of experimental diets. Hemoglobin Ai, was lower and serum insulin level was higher in GO group than CO group without significance. These results suggest that r-oryzanol decrease the blood glucose level, and ${gamma}$ -oryzanol produced from residual product of rice may be developed with high value.