A novel omni-directional UHF RFID tag antenna is proposed. The structure consists of four identical arrowtyped blocks. The proposed antenna has a bandwidth of 244MHz with the reflection coefficient to be below -10dB. Test result shows that the proposed antenna has exhibited a very good omni-directional reading pattern as compared to conventional tags based on planar dipole antennas. As a result, the proposed antenna eliminates orientation-related missed reads or blind spots.