The effect of addition the red beet extract to the food of mulberry silkworm, Bombyx mori as a supplements at three concentrations i.e. 25, 50 and 100% was investigated during the last larval instar. The mean weights of mature larvae, silk gland, fresh cocoon, pupae, and cocoon shell were recorded as indicator for growth and silk production of mulberry silkworm. All concentrations of red beet extract showed a significant increase in all traits of silkworm treated larvae. The concentration of 50% of red beet gave the best records which significantly enhanced the all traits (mature larvae, silk gland, fresh cocoon, pupae and cocoon shell) by 7.8, 27.94, 35.54, 35.19 and 31.6% higher than control, respectively. This study indicated that the red beet supplement can be used to increase the silk yield in commercial silkworm.