Abstract: In order to save time and labor and reduce risk of injury to the livestock or to the people while measuring changes in the body weight monitoring of grazing livestock, a new livestock weighing system was invented and evaluated in this paper, which involved an E-tag fitting to each animal, and using a RFID reader, an electrical scale and special software. The result showed that the new livestock weighing system can save more than 70 percent of labor and 50 percent of the weighing time compared to the traditional way, and avoid the dangers associated with handling large livestock. By using of the E-tag based on the RFID technology, the monitoring of body weight and body condition for individual livestock is now possible.