We report an energy-autonomous Radio Frequency IDentification (RFID) tag system which is powered by an electrostatic MEMS-based Vibration Energy Harvester (e-VEH). The VEH is designed specifically for the vibrations of low frequency around 10 Hz. An energy of 80 nJ/cycle can be delivered when the VEH is loaded with an optimal resistor and a bias of 20 V. An RFID chip is powered by the current released from a 1-μF capacitor, which is charged by the VEH through a diode rectifier. The read range of the tag is increased from 2.5 m (under batteryless mode) to 15 m when powered by the VEH working with an acceleration of 2 grms and 10 Hz. The energy of the VEH stored in the capacitor within 40 s can sustain up to 3 tag readings.